4

Hormonal Management of Male Infertility

Alaa Hamada, Deepinder Goyal, Ashok Agarwal

pituitary gonadotropins have been proved to be essential Chapter Contents for in utero differentiation of male reproductive organs. During puberty, testicular steroidogenesis and sper­ ♦♦ Physiological Overview matogenesis are under the control of hypothalamic pitui­ ♦♦ Hypothalamic Pituitary Gonadal Axis (HPG) tary gonadal (HPG) axis. Hypothalamic pituitary gonadal ♦♦ Clinical Endocrine Evaluation of Infertile Man axis mainly consists of three endocrine organs: hypo­ ♦♦ Diseases of the HPG Axis thalamus, anterior pituitary gland and testes, secreting ♦♦ Diseases of the Adrenal Glands peptide, protein and steroid hormones. The hormonal ♦♦ Thyroid Disorders secretions are under positive and negative feedback ♦♦ Excess Estrogen control at multiple levels of the HPG axis. Furthermore, ♦♦ Diabetes Mellitus and Metabolic Syndrome contribution of higher brain centers, hypothalamic and ♦♦ Hormonal Intervention in Male Infertility pituitary hormonal secretion and other endocrine organs, ♦♦ Cytoprotective Hormonal Effects on Sperm in Cancer such as thyroid and adrenal glands, also exerts regulatory Patients role. The scope of this chapter is to present a brief physio­ logical overview about hormone structure, transport in the blood, receptor, metabolism and target organ action. Later, the physiological and the pathological conditions of INTRODUCTION male reproductive endocrinology will be examined with particular emphasis on the role of endocrine therapy in arious hormones regulate the male reproductive treatment of male infertility. Vfunction through well integrated complex set of interactions in various developmental stages. In utero sexual differentiation of the male external genitalia and PHYSIOLOGICAL OVERVIEW internal reproductive organs is hormonally mediated through fetal testicular secretion of testosterone. Around Hormones are chemical molecules secreted by special­ 7th to 8th week of gestation, fetal Leydig cells begin ized group of cells to exert specific action or effect on de novo synthesis and secretion of testosterone. Such target cells or body system through binding with specific secretion is initially maintained by placental human receptors. The secreting cells, scattered or organized chorionic gonadotropin (hCG) and subsequently by fetal in glands, usually release their contents into the extra­ pituitary luteinizing hormone (LH) in the latter half of cellular (EC) space. Based upon the mode of hormone the gestation. However, neither placental hCG nor fetal delivery and the target cells, three types of hormonal Section 2 Male Factor Infertility

effects are recognized. Paracrine effect is seen when the storage capacity of the steroidogenic cells; however, secreting cells affect other target cells in their vicinity, under effect of specific stimuli large amount of choles­ usually in the same organ or tissue, and the EC fluid is teryl ester can be mobilized from cytoplasmic vacuoles the transporting medium. Autocrine effect is exhibi­ted to SER for immediate synthesis and release of steroid when the released hormone exerts biological effect on hormones. the same cell of origin. Endocrine effect is described Hormones are the second key regulator of the human when the hormones are transported through the blood body systems’ functions after the nervous system. They stream to bind with their target cell receptors, which are are instrumental in maintenance of internal homeostasis, usually in other organs or systems of the body. Lastly, response to stressful condition, water and salt balance, the fourth mechanism, known as intracrine, is demon­ metabolic regulation, energy production, growth and strated when the synthesized hormone acts intracellu­ behavior, and human reproduction. The later function larly in the same cell before release. is fundamentally based on the integrity of complex set Essentially, three classes of hormones are identified of hormonal interaction, known as HPG axis. based upon the chemical structure: amino acid (usually tyrosine) derivatives, peptides and proteins hormones Transport of Hormones in the Blood and steroid hormones. For instance, tyrosine derived Peptide, protein hormones and some amino acid derived hormones encompass thyroxin, epinephrine, norepi­ hormones, such as catecholamines, are water soluble and nephrine (NE) and dopamine (DA). On the other hand, therefore freely distribute in the blood stream, reaching peptide and protein derived hormones constitute the their target receptors without the need for carrier proteins. majority of hormones in human body. Specifically, the However, steroid and thyroxine hormones are poorly peptide hormones consists of fewer than 100 amino water soluble and circulate in the blood mainly bound acids and vary considerably in size, ranging from three to plasma proteins, such as sex hormone binding globu­ amino acids peptide, such as thyrotropin releasing lins (SHBGs), corticosteroid binding globulin, thyroxine hormone (TRH) to as much as 84 amino acids polypep­ binding globulins (TBG) respectively and albumins. The tide hormone represented by parathyroid hormone. biologically inactive protein-bound hormone constitutes Protein hormone is often composed of more than 100 the major hormonal fraction, conferring three important amino acids and may reach up to 200, such as growth physiological properties. Firstly, it acts as a reservoir hormone (GH) and prolactin (PRL). Peptide and replacing the biologically active free hormone when they protein derived hormones are often synthesized in the are bound to their target receptors or lost from the circu­ rough endoplasmic reticulum (RER) as large precursor lation and secondly, prevents rapid clearance of small hormones (preprohormones) that are then cleaved into sized molecules in urine or bile and prolongs their half- prohormones and transferred to Golgi apparatus. Inside lives. Thirdly, it ensures ubiquitous hormonal distribu­ Golgi apparatus, packaging and storage of prohormones tion in various body organs. Interestingly, pathological into secretory vesicles occur, where they undergo the and physiological increase in the carrier proteins may final modification and cleavage into active hormones and inactive residues. Certain cellular stimuli, such as increased cytoplasmic calcium or c-AMP trigger fusion of these granules with plasma membranes and release of their contents into interstitial fluid or directly into the blood by the process, known as exocytosis.1 Peptide hormones are generally water soluble and easily trans­ ported to their target organs. Lastly, steroid hormones, a class of lipids derived from cholesterol, include cortisol, aldosterone, testos­ terone, progesterone and estrogen. Minor biochemical differences among these hormones result in variable physiological role and function. These hormones are synthesized in the smooth endoplasmic reticulum (SER) and secreted from steroidogenic cells in testes, ovaries, adrenal cortex and placenta. Structurally, these steroid hormones consist of three cyclohexyl rings and one cyclopentyl ring combined into a single struc­ 58 ture (Figure 1) and are lipid soluble. There is a limited Figure 1 Chemical structure of several steroid hormones Chapter 4 Hormonal Management of Male Infertility ultimately result in false elevation in total hormone C with production of inositol triphosphate (IP3) and measurement assays. Measurement of the physiologi­ diacylglycerol (DAG). Inositol triphosphate increases cally active component, free hormone fraction, is useful intracellular calcium as second messenger, while DAG in these situations. However, unreliability of some of activates protein kinase C with further phosphorylation these assays necessitates simultaneous determination of of intracellular proteins. Examples of G-protein linked total hormone level and hormone binding globulin or receptors that activate adenylatecyclase include LH, preferably calculating the free hormones by equilibrium follicle-stimulating hormone (FSH), thyroid-stimulating dialysis method. hormone (TSH) and corticotropin-releasing hormone (CRH); whereas, examples of G-protein linked recep­ Hormone Action at the Target Organ tors activating phospholipase C encompass LH, FSH, Covalent binding of a hormone ligand with its specific Gonadotropin releasing hormone (GnRH) and thyro­ receptor in the target organ is the first step in the tropin-releasing hormone (TRH). hormonal action, initiating a cascade of events that ulti­ Intracellular receptors are the second major class mately result in expression of the response. For a cell or family of hormone receptors and include up to to adequately respond there should be at least 2,000– 150 members. These receptors are, in fact, hormonally 100,000 high affinity receptors, represented by large regulated transcription factors which upon binding with proteins undergoing dynamic interaction on binding.1 specific hormone, bind to specific DNA sequences close The receptor sites and number vary based upon the type to promoter sites controlling the expression of certain of hormone and the receptor itself. Protein, peptide and genes. This class is further classified into cytosolic recep­ catecholamines usually attach to cell plasma membrane, tors, e.g. steroid hormone receptors, and nuclear recep­ receptors. The response is relatively fast and depends tors, e.g. thyroid hormone receptors. on signal transduction and activation of a second After receptor activation, hormone-receptor complex messenger. Nonetheless, some protein hormones, such either dissociates leaving the receptor free or the complex as insulin, PRL and gonadotropins can enter the cells is internalized by endocytosis, degraded inside lysosomes as well. Steroid and thyroid hormones, on the other and the receptor is then recycled again. Nevertheless, hand, bind to cytoplasmic receptors (and then translo­ receptor availability, number and affinity are not static, cated to the nucleus) and nuclear receptors respectively, and instantaneous steady state equilibrium exists between resulting in a slower response in the form of hormone- the hormone and its receptors. For instance, increased receptor complex induced activation of DNA transcrip­ hormone concentration with consequent increased tion and translation. For steroid target cells 3,000–10,000 receptor binding eventually results in decreased avail­ cytoplasmic receptors should be present to illicit a ability of the receptors and thus minimizing the target hormonal response.1 cellular response to the hormone and the process is called Two major classes or families of hormone receptors ‘downregulation,’ e.g. continuous administration of are recognized: cell surface receptors and intracellular GnRH results in decrease in the pituitary gland synthesis receptors2 (Figure 2). Cell surface receptors are specifi­ and release of FSH and LH. Conversely, some hormones cally classified according to molecular mechanism of or stimulating substances increase manufacturing of signal transduction into: group A (the receptor is linked receptors and hence the target cell response to stimulating to tyrosine kinase activity inducing intracellular phos­ hormone, e.g. thyroxine increases the receptor response to phorylation) that is further subdivided into subgroup I catecholamines. receptor that has intrinsic tyrosine kinase activity, such as insulin and growth factors’ receptors, and subgroup Metabolism, Degradation and II receptors that recruit tyrosine kinase activity, such as Clearance of Hormones cytokines, GH, PR Land leptin’s receptors. On the other Following activation of target receptor tissues, a small hand, group B receptors are coupled with GTP-binding fraction of hormones usually undergoes in situ enzy­ protein (G-protein linked receptor) and there are more matic inactivation and degradation; whereas the than 1,000 known types of G-protein linked receptors. remaining large portion is inactivated and excreted GTP linked receptors have extracellular portion, seven through the liver and/or the kidney. Less than 1% of looped transmembrane portion and intracellular cyto­ any hormone is excreted unchanged in urine. Metabolic plasmic tail. On binding with a ligand, G-protein linked inactivation includes oxidation, hydrolysis, hydroxyla­ receptors undergo conformational changes replacing tion, methylation, decarboxylation, sulfation and glucu­ GTP for the GDP (already attached to the cytoplasmic ronidation. However, some hormones can be enzy­ tail) and activate either adenylatecyclase with produc­ matically activated to more potent forms at the target tion of cAMP as second messenger or phospholipase tissues, such as conversion of tetraiodothyronine (T4) to 59 Section 2 Male Factor Infertility

Figure 2 A composite diagram showing the different classes of hormone receptors Abbreviations: PLC, phospholipase C; TK, tyrosine kinase Source: Brook CG, Rosalind SB. The application of science to clinical practice. In: Brook CG, Brown RS (Eds). Handbook of Clinical Pediatric Endocrinology, 1st edition. Massachusetts, USA: Blackwell Publishing, Inc; 2008.pp. 1-13

tri-iodothyronine (T3) and conversion of testosterone to pallidus and ansa lenticularis4 (Figure 3). Within this dihydrotestosterone (DHT). loose network of neurons, several nuclei are discernible. Hypothalamus is mainly divided into two main parts: medial and lateral. In the medial part, three nuclear HYPOTHALAMIC PITUITARY GONADAL groups are identified: anterior, middle and posterior. AXIS (HPG) In the anterior group three nuclei are located: suprachi­ asmatic nuclei (biological clock),5 paraventricular and Hypothalamus supraoptic nuclei. The middle group includes again three nuclei ventromedial, dorsomedial and arcuate Hypothalamus is a vital neuroendocrine organ, repre­ nuclei; whereas, in the posterior group of the medial part, senting an important link between nervous and endo­ two nuclei are seen: posterior nucleus and mammillary crine systems. Hypothalamus is essentially composed of body (Figure 3). The lateral portion of the hypothalamus loose network of neurons defined by arbitrary borders, is mainly composed of nerve fibers (lateral forebrain located below the thalamus and above the brainstem bundle) and loosely arranged nerve cells. forming the ventral portion of diencephalon. It is a Hypothalamus acts as an integrative unit receiving small organ of an almond size (1.5 cm x 1.5 cm x 1.3 cm), afferent fibers from limbic structure, brain cortex, taste weighing about 2.5 gm,3 bound anteriorly by ante­ and olfactory stimuli, gastrointestinal and cardiovas­ rior margin of the optic chiasm and lamina terminalis, cular system. Efferent fibers are widespread and include posteriorly by the posterior margin of the mammillary projections to three main regions: pituitary gland, cere­ bodies, and laterally by a diffuse line extending from bral cortex and autonomic nervous system. In addition, 60 the optic tracts, internal capsule, pes pedunculi, globus hypothalamic neurons respond to other stimuli, such Chapter 4 Hormonal Management of Male Infertility

median eminence, whereby vascular networks stemming from superior hypophyseal artery are transporting them through a big vein, hypophyseal portal vein, to another capillary network into the pituitary gland. These releasing and inhibitory factors exert specific effects on a parti­ cular group of pituitary cells to elicit a release of a specific hormone. Specifically, hypothalamic neuropeptides that are mainly concerned with male reproduction are divided into: Peptides with direct influence on male reproduction. These include GnRH, CRH, and prolactin inhibitory factor (PIF). Peptides with indirect influence on male reproduction. These include TRH, growth hormone releasing hormone (GHRH) and growth hormone inhibiting hormone (GHIH). Gonadotropin Releasing Hormone Gonadotropin releasing hormone is a hypothalamic decapeptide controlling the secretion of gonadotro­ pins, FSH and LH from the anterior pituitary. GnRH is released in a pulsatile pattern from a diffuse network of Figure 3 The hypothalamus. Median section through the 1,500 neurons that are mainly concentrated in medial third ventricle. Some of the major hypothalamic nuclei are basal hypothalamus, the infundibulum, and periven­ shown with colored dots. The size of the dots indicates the tricular region.6-8 These neurons act as a single pulse relative size of neurons of various nuclei. generator for the HPG axis. GnRH pulse release lasts for Source: Brodal P. The central autonomic system: the hypothalamus. In: Brodal P(Ed).The Central Nervous System Structure and Function, few minutes at frequency of one pulse every 1–3 hours. 4th Edition. Oxford: Oxford University Press; 2010.pp. 440-58. The amount of GnRH is determined by the quantity of GnRH secreted at each pulse and the frequency of these cycles (Figure 5). Correspondingly, LH is secreted from as hormones, changes in blood sodiumconcentration, the anterior pituitary at pulse frequency exactly coin­ temperature and volume variations. In response to these ciding with that of GnRH; whereas, FSH shows nonpul­ stimuli, the hypothalamic neurons activate the regula­ satile mode of secretion and even when it is pulsatile, tory physiological mechanisms achieving homeostasis. there is little concordance with GnRH pulses. Exogenous Hypothalamic cells contain specific receptors for replacement of GnRH should follow similar physio­ hormones, such as sex steroids, thyroid hormones, adrenal logical regulations to stimulate LH and FSH secretion. steroids, leptin and hormones released from the ante­ Chronic continuous administration of GnRH may result rior pituitary. Communication of the hypothalamus and in inhibition of LH and FSH.9 pituitary gland is unique, represented by vascular circuit with the anterior pituitary, and neural circuit with poste­ Pituitary Gland rior pituitary (Figure 4). Hypothalamic projections from Pituitary gland is an essential endocrine organ in the paraventricular and supraoptic nuclei directly release human body. It is composed of three components: anterior oxytocin and antidiuretic hormone from the nerve termi­ lobe (adenohypophysis, predominant part), intermediate nals endings into the posterior pituitary and thereby, lobe (vestigial component) and posterior lobe (neurohy­ hormones are transferred to the blood stream. Such projec­ pophysis). Pituitary gland is located in the bony sellatur­ tions form the neural circuit, hypothalamo-hypophyseal cica at the base of the skull, overlaid by thin diaphragm, tract. Alternatively, the connection between hypotha­ through which the pituitary stalk connecting between the lamic nuclei and anterior pituitary is mainly through pituitary gland and median eminence of hypothalamus the vascular circuit ‘the hypophyseal portal system’ and is passing through. Its average weight is 400–900 mg and the short neural circuit tuberoinfundibular tract. Axons measures about 13 mm in the longest transverse diameter, from the hypothalamic nuclei forming tuberoinfundib­ 6–9 mm vertically, and about 9 mm anteroposteriorly.10 ular tract secrete releasing and inhibitory factors into the Adenohypophysis is the major endocrine portion of the 61 Section 2 Male Factor Infertility

A B

C Figures 4A to C Relationship between the hypothalamus and the pituitary gland. (A) Connections from the hypothalamus to the posterior lobe; (B) The portal vessels of the pituitary stalk ensure that releasing hormones (factors) are transported from the median eminence in the upper part of the stalk to the epithelial cells of the anterior lobe; (C) Axonal transport of peptide hormones (neuropeptides) from the hypothalamus to the pituitary Source: Brodal P. The central autonomic system: the hypothalamus. In: Brodal P(Ed). The Central Nervous System Structure and Function, 4th edition. Oxford: Oxford University Press; 2010.pp. 440-58

pituitary gland, consisting of gonadotrophs (5–10%), and biological activity. Around 60% of gonadotrophs somatotrophs, thyrotrophs and corticotrophs.11 Under secrete both FSH and LH; whereas, 18% and 22% of cells the effect of GnRH, gonadotrophs secrete LH and FSH solely secrete LH and FSH respectively.10 directly into the blood stream to exert their effects on Glycosylation of these hormones with various types testicular Leydig cells and Sertoli cells, respectively. of oligosaccharides occur before release from the pitui­ tary cells, consisting of various types of sugars, such as Gonadotropins sialic acid, mannose, galactose and N-acetylglucosamine. Luteinizing hormone and FSH belong to a family of There are two sites of glycosylation in each peptide glycoprotein hormones that also includes TSH. Each chain.12,13 Single branched; di-,tri- and even tetra- glycoprotein hormone in this family is heterodimeric, branched oligosaccharides are demonstrated in these i.e. consisting of α-chain and β-chain. The α-chain is a glycosylation sites that lead to appearance of different common chain, whereas β-chain confers functional spec­ isoforms of the gonadotropin. These sugars have effect ificity for a particular hormone. These chains are tightly on hormone assembly, secretion pattern, mode of action linked by disulfide bonds, yielding specific conforma­ and metabolic clearance.2,12 Sialic acid residues are the 62 tional structure which is necessary for receptor binding most critically important sugar in these oligosaccharides Chapter 4 Hormonal Management of Male Infertility

androstenedione. Testosterone is the most abundant hormone and 75% of blood testosterone is derived from testes. 200 x 106 Leydig cells daily secrete 4–9 gm of testosterone under the effect of LH.17 Furthermore, insulin-like factor 3 (INSL3) is another protein hormone secreted by Leydig cells, which may be used as an indi­ cator of Leydig cell function. INSL3 has been postulated to play a direct role in regulation of sperm production.17

Testosterone: It is the main hormone secreted by the Leydig cells of testes and is the principal androgen in men. It is C19 steroid hormone with OH group at position C17 in the sterol ring. Testosterone is important for regulation and induction of spermatogenesis and development of Figure 5 The influence of GnRH pulse frequency on LH and FSH secretion in a female rhesus monkey with an arcuate secondary sexual characteristics. Leydig cells synthesize nucleus lesion ablating endogenous GnRH support of the testosterone, under the effect of LH, from two sources: pituitary. Decreasing GnRH pulse frequency from 1 pulse/ cholesterol, or synthesized de novo or taken directly hour to 1 pulse/3 hours leads to a decrease in plasma LH from the blood. Androstenedione is synthesized by the concentration but an increase in plasma FSH concentrations. adrenal glands. LH stimulates mitochondrial uptake of Source: Wildt L, Haulser A, Marshall G, et al. Frequency and amplitude cholesterol by enhanced activity of steroidogenic acute of gonadotropin-releasing hormone stimulation and gonadotropin regulatory protein, the first rate-limiting step in testos­ secretion in the rhesus monkey. Endocrinology. 1981;109:376-85.92 terone synthesis. Inside the mitochondria, cholesterol undergoes side change cleavage to form pregnenolone that leads to appearance of gonadotropin isoforms.13 that diffuses outside the mitochondria towards SER Acidic isoforms that have more sialic acid residues in where it is further processed. Two important pathways the attached oligosaccharides often have longer half-life are embarked toward formation of testosteroneinside and are relatively protected from degradation by the SER: d5-pathway (pregnenolone, 17OH pregnenolone liver, whereas less sialic acid residues render gonado­ and dehydroepiandrosterone (DHEA) and androsten­ tropins less acidic and more potent.9 The half-life of LH ediol) and d4-pathway (pregnenolone, progesterone, (< 20 minutes) is relatively shorter than that of FSH 17OH progesterone and androstenedione). d5-pathway (1–4 hours). GnRH and sex steroids play critical role in predominates in human testes. Synthesis of testosterone regulating the process of glycosylation.9 by testis requires the presence of two specific enzymes: Various studies have shown progressive increase 17b-hydroxysteroid dehydrogenase-3 that catalyzes the in the serum levels of FSH and LH with aging.14,15 FSH conversion of DHEA to androstenediol and conversion secretion increases in both continuous and pulsatile of androstenedione to testosterone, and 3b-hydroxys­ forms; whereas, LH shows modest but inconsistent teroid dehydrogenase-2 that directly converts andros­ elevation in the elderly men.16 Such rise in gonadotropin tenediol to testosterone. level is attributed to impaired testicular feedback regu­ As aforementioned, human testis daily produces lation of the hypothalamus and pituitary gland. 4–9 gm of testosterone. In addition, 500 mg of testostero­ neis produced either directly from the adrenal glands Testes or from peripheral conversion of androstenedione. DHT Testis is the third component of the HPG axis. is another hormone produced by the testis through Functionally, testis is divided into two compartments: enzymatic action of Sertoli cell-derived 5-α-reductase interstitial compartment containing Leydig cells, and on testosterone. However, only 20% of serum DHT seminiferous tubules consisting of Sertoli cells and sper­ is secreted by the testes and the rest is derived from matogenic cells in various stages of development. peripheral conversion at the target tissues. DHT has more than twice the biological activity of testosterone. Leydig Cell Alternatively, testosterone and androstenedione can be Leydig cells constitute about 10–20% of interstitial converted to estradiol and estrone respectively by the compartment that forms 12–15% of testicular volume.17 action of aromatase enzyme in the gonadal and extrago­ Leydig cells secrete group of hormones collectively nadal tissues, as will be described below. The major cata­ known as androgens including testosterone, DHT and bolic pathway of testosterone to less active metabolite is 63 Section 2 Male Factor Infertility

mainly through conjugation in the liver and excreted in hormone secretion) or positive (stimulate hormone urine as 17-ketosteroids. secretion). These loops include: Long feedback loop in which the secretion of testis Estrogens: Although small amount (20%) of estrogen (the target organ) inhibits or stimulates hypothalamus in men is directly secreted by the testis, the majority is and anterior pituitary secretion derived from conversion of testosterone and andros­ Short feedback loop in which the anterior pituitary tenedione by aromatase enzyme inside gonadal cells, secretions control the hypothalamic hormonal output such as Leydig cells and Sertoli cells and extragonadal Ultrashort feedback loop in which there is intrinsic tissues, such as brain, skin, liver, mammary tissues, and regulation of hormonal output at each organ or level of most significantly, the adipose tissue. The plasma level HPG axis of estradiol is 2–3 ng/dL with production of about 25–40 In the first loop, testosterone is the major hormone µg per day. The exact physiological role of estrogen in released by testis and regulates GnRH and gonado­ male reproductive function is under investigation. While tropin secretion. Specifically, testosterone or its metabo­ estradiol plays an inhibitory role in regulation of HPG lite DHT reduces the frequency of hypothalamic pulse axis at the level of hypothalamus and pituitary glands, generator to release GnRH, whereas testosterone or its recent investigations revealed presence of estrogen metabolite estrogen acts on pituitary cells to inhibit GNs receptors (ERα) in the efferent ductules, epididymis and release.17 Higher doses of testosterone can also exert Leydig cells. Knockout male mice for ERα suffer altera­ inhibitory effect on GnRH and LH; however, it directly tion of spermatogenesis and infertility. However, expo­ stimulates pituitary FSH secretion through positive sure to exogenous estrogen can suppress HPG axis and feedback loop interaction.19 Progesterone, on the other impair spermatogenesis. Further studies on humans hand, acts on dopaminergic arcuate nucleus neurons may be needed to uncover the complete physiological that inhibit GnRH neurons.20 Additionally, other testic­ roles of estrogen. In men, in contrast to women, estra­ ular factors, such as activin and inhibin, stimulate or diol level increases with age. inhibit pituitary release of FSH respectively at the level of pituitary gland (Figure 6). Sertoli Cells Evidence for pituitary influence on hypothalamic Sertoli cells perform supporting role in orchestrating the secretion arises from identification of a direct inferior process of spermatogenesis and in forming the blood branch of the hypophyseal artery entering the anterior testis barrier. Approximately, 35–40% of the volume pituitary gland in some mammals and finding that blood of germinal epithelium is represented by Sertoli cells.18 flow within the portal system can occur in the reverse The intact testis contains 800–1200 × 106 Sertoli cells or (retrograde) direction—from anterior lobe toward approximately 25 × 106 Sertoli cells per gram testis.17 hypothalamus. Therefore, the pituitary gland might Sertoli cells secrete variety of proteins, cytokines, regulate the hypothalamus by ‘short-loop’ feedback.21 growth factors, opioids, steroids, prostaglandins and The ultrashort hypothalamic feedback is represented modulators of cell division. Specifically, Sertoli cells by paracrine and autocrine regulation of GnRH neurons. secrete two structurally related proteins, i.e., inhibin GnRH neurons can regulate the secretory activity of their and activin. These proteins are dimers belonging to own and there is evidence for the presence of receptors transforming growth factor-β family. Inhibin consists of for GnRH (GNRHR) in hypothalamic neurons.21 Neurons an α subunit and a βA or βB subunit, whereas activin is from limbic system, brain stem and other hypothalamic a homodimer (βAβA or βBβB). Inhibin is secreted from areas project to GnRH neurons and influence their Sertoli cells under the effect of FSH and acts to inhibit secretory activity. Neurons that release glutamate and FSH secretion from the anterior pituitary. Conversely, NE provide stimulatory role to the reproductive axis; activin activates secretion of FSH to stimulate spermato­ whereas, those neurons that release gamma aminobu­ genesis. These hormones are not only secreted by Sertoli tyric acid(GABA) and endogenous opioid peptides play cells, but also from other sources, such as Leydig cells, important inhibitory role.17 prostate, liver etc. Within the pituitary gland, nerves and short portal vessels interconnect the pituitary lobes forming potential Regulation of HPG Axis routes of intrapituitary communication and regulation. On each level of HPG axis, three types of regulatory Finally, testis is a complex endocrine organ,where various feedback loops are acting to control hormonal output. mechanisms of ultrashort regulatory loops exist in the These regulatory loops are either negative (inhibit form of paracrine, autocrine and even intracrine systems. 64 Chapter 4 Hormonal Management of Male Infertility

Figure 6 Schematic figure shows the complex regulation of hypothalamic pituitary gonadal axis. Well-balanced nutrition, moderate exercise and seasonal cues have stimulatory effects on the hypothalamus through higher brain centers, whereas excessive exercise, undernutrition may have inhibitory effect on the hypothalamus. Factors stimulating GnRH neurons to release GnRH include norepinephrine (NE), neuropeptide Y (NPY), leptin, galanine like peptide(GALP) and glutamate; whereas, factors inhibiting central GnRH release include beta endorphins, interleukine1, GABA, corticotropin releasing hormone (CRH) and dopamine (DA). The figure also shows negative feedback regulation of gonadotropin synthesis and release. Testosterone, DHT, estrogen, progesterone and inhibin B are factors released from the testes and inhibit gonadotropin release at the level from the hypothalamus and the pituitary gland. Activin is released from many cells in the male reproductive system and locally produced in the pituitary to stimulate FSH release. Source: Low MJ. Neuroendocrinology. In: KronenberHM, Melmed S, Polonsky KS, Larsen PR(Eds). Kronenberg And Williams Textbook of Endocrinology,11th edition. PhiladelphiaPA: Saunders; 2008. pp. 85-135

65 Section 2 Male Factor Infertility

CLINICAL ENDOCRINE EVALUATION OF disturbances in the HPG axis (24%) should always be 24 INFERTILE MAN sought. In adults who have already completed pubertal Initial evaluation of infertile couple should aim at spurt, features of hypogonadism include loss of energy determining whether the problem lies within the male and decrease in libido. Tables 1 and 2 show signs of male or female partner, or both. If the female partner has hypogonadism before and after puberty. regular menstrual cycles; patent fallopian tubes; normal Physical examination (general and genital) adds a FSH, LH, TSH and PRL levels; male factor infertility wealth of information. Tanner staging is essential compo­ is the likely cause.22 Clinical evaluation of endocrine nent of physical assessment. Arms span and its discord­ contribution to male factor infertility should commence ance with the body height, excessive skin pallor, sparse with detailed history taking and proper conduction of pubic and facial hair distribution, female fat distribution, physical examination. Four important goals of endo­ diminished testicular size, and presence of gynecomastia crinological evaluation are to assess: may all pinpoint to potential endocrine deregulation as 1. Whether male reproductive dysfunction is attributed a cause for infertility. Physical examination could even to male hypogonadism or not. suggest the possible mechanisms and the exact site of 2. Prepubertal or postpubertal onset of hypogonadism. endocrine disturbance. Visual field defects, galactorrhea 3. Whether the problem is localized to the HPG axis or and impotence may indicate prolactinoma associated outside this axis. hypogonadism. Lack of smell sensation is a diagnostic 4. Finally, if the defect has been traced to HPG axis, feature of Kallmann’s syndrome. Gynecomastia, bilat­ specific testicular, pituitary or hypothalamic etiology eral small testes and behavioral problems may indicate should be sought and then treated. Klinefelter’s syndrome. Varicocele, bilateral testicular Certain childhood illnesses, such as unilateral or bilat­ atrophy, testicular mass, signs of chronic liver or kidney eral empty scrotum, testicular torsion, scrotal trauma, diseases, obesity, signs of Cushing’s syndrome, acro­ pediatric inguinal hernia repair and mumps orchitis megaly, thyroid dysfunction all can probably shed a could risk not only the spermatogenesis function, but light on the etiology behind hypogonadism. also Leydig cell function as well. Defective testosterone­ Semen quality should be determined by analyzing synthesis or action in the third trimester could result in semen samples obtained by masturbation after 2–7 male live births born with ambiguous genitalia, cryp­ days of abstinence. Semen volume, pH, sperm count, torchidism and micropenis. Other risk factors for male hypogonadism include testicular tumors; exposure to certain medications, such as anabolic steroids, cimeti­ Table 1 Signs of early onset hypogonadism dine, ketoconazole, digoxin and spironolactone; cancer • Eunuchoid appearance: arm span > 5 cm than height chemotherapy or radiotherapy; HIV/AIDS; hemo­ • Poor musculinization chromatosis; pituitary tumor and surgery and certain • Lack of recession of hair on temporal lobe systemic inflammatory and infectious conditions, such • Sparse axillary, pubic, facial and body hair as sarcoidosis, chronic obstructive airway diseases, • High-pitched voice chronic liver and kidney diseases, histiocytosis, tuber­ • Small testes and possibly maldescended culosis and fungal infections. Furthermore, substance • Infantile external genitalia abuse and recreational drugs, such as marijuana, heavy • Impaired libido and potency smoking, cocaine and alcohol have been also implicated • Oligospermia to azoospermia in the etiology of male hypogonadism. Absent or delayed pubertal development is ominous Signs of postpubertal onset of sign of male hypogonadism. In approximately 99.5% of Table 2 androgen deficiency white boys, early signs of secondary sex characteristics may at least become evident by the age of 14 years.23 • Normal body proportions with possibility of osteoporosis Increased testicular volume from 1–2 cc to 3–8 cc accom­ • Atrophy and decreased muscle strength panied by discernible enlargement of penile size are the • Male-pattern baldness first signs of puberty and typically such signs occur at • Sparse facial, pubic, axillary, chest and hair • Normal pitch of voice the age of 11.5 years in most US boys.23 Although the • Small, often soft testes most common cause of pubertal delay is constitutional • No change in the size of external genitalia [idiopathic delay (60%)] and delayed but spontaneous • Decreased libido and erectile dysfunction pubertal developmental [functional hypogonadotropic • Oligospermia to azoospermia 66 hypogonadism (HH) 20%], permanent endocrine Chapter 4 Hormonal Management of Male Infertility density, motility, morphology and viability are evalu­ FSH level often indicates significant alteration in sper­ ated in accordance with WHO criteria.25 It is important matogenesis. On the other hand, low FSH in the pres­ to obtain multiple semen samples to overcome tremen­ ence of low testosterone may reflect central disorder dous variability in sperm parameters. in the HPG axis, such as HH. In contrast, normal FSH measurement may not be indicative of normal spermato­ Indications of Endocrine Testing genesis and does not exclude severe derangement of In two large retrospective analyses of 1,035 infertile men spermatogenesis. Specifically, men with spermatogenic in two infertility centers, endocrine abnormalities, on arrest at late stages, focal Sertoli cell only syndrome and repetitive testing, had been detected in only 99 patients hypospermatogenesis may all have normal FSH level.29 (9.6%). FSH elevation was the most frequent abnor­ Even more specifically, normal FSH is not absolute mality.26 Furthermore, only 1.75% of these men had predictive parameter of sperm retrieval by testicular clinically relevant endocrinopathy in terms of disease sperm extraction in men with NOA.29,30 From the above management.26 discussion, it is apparent that the value of serum FSH Interestingly, with presence of relatively normal measurement is particularly limited and determination spermatogenesis, detecting low levels of FSH or LH has of other endocrine factors, such as inhibin B, may be no clinical significance. The current recommendations of required to represent the quality of spermatogenesis. endocrine testing include: Inhibin B is a direct product of Sertoli cells and its • Sperm concentration less than 10 million/ml serum levels have been found to be better correlated • Erectile dysfunction and decreased libido to sperm parameters than FSH and thus may serve as • Hypospermia (semen volume < 1 ml) a better marker of spermatogenesis.31 Inhibin B levels • Signs and symptoms of endocrinopathies, such as can also be useful for monitoring the effects of gonado­ thyroid dysfunction, acromegaly, delayed puberty tropin therapy. However, inhibin B or FSH alone as well or hypogonadism as the combination of both hormones cannot predict the • Presence of gynecomastia finding of spermatozoa by testicular biopsy in patients • History suggestive of hyperprolactinemia, such as with azoospermia who are candidates for intracyto­ headache, galactorrhea, impotence, blurred vision plasmic sperm injection(ICSI) treatment.32 • Testicular mass Testosterone level is, more or less, a good indicator • History of exogenous estrogen or androgen exposure of the integrity of HPG axis and Leydig cell function. • Significant obesity Total testosterone level consists of protein (SHBG and • Clinical features of androgen resistance albumin) bound fraction (98%) and free fraction (2%), • Clinical picture consistent with 5-α reductase­ and its measurement correlates well with available deficiency testosterone. However, measurement of free testo­ Clinical fertility centers differ in the extent of sterone should be considered when alterations in SHBG hormonal evaluation for infertile men. Current American are expected (Table 3). In order to determine free testo­ Urological­ Association (AUA) guidelines recommend sterone reliably, equilibrium dialysis or ultrafiltration­ the measurements of at least serum FSH levels and techniques are required. These methods are complicated serum testosterone levels in patients suspected of having and not routinely recommended at present. However, abnormality in HPG axis.27 Such measurements are a simple and reliable method for clinical practice is the reliable in detecting 99% of endocrine abnormalities.28 estimation of free testosterone from the levels of total Testosterone is considered the indicator of endocrine testosterone, and SHBG by using a standard equation balance and normal functioning of Leydig cells, whereas and special nomograms (Fig. 7).33 Calculated free testo­ FSH level is thought to be a representative parameter of sterone correlates well with free testosterone estimated spermatogenesis. by equilibrium dialysis.34 The serum total testosterone However, many centers carry out a more extensive concentration is not diagnostic of hypogonadism in laboratory evaluation, which can include measurement obese patients or those with nephrotic syndrome, hyper- of LH, PRL, serum inhibin B, TSH, SHBG, cortisol and or hypothyroidism, chronic liver disease, or on therapy estradiol levels, if the clinical findings indicate an endo­ with anticonvulsants or steroids.34 crine abnormality. The generally approved reference range for total Serum FSH measurement may reflect the state of testosterone in adultmen is wide, from 260 ng/dl to spermatogenesis in infertile men. As aforementioned, 1,000 ng/dl(9–34.7 nmol/l). Furthermore, testosterone elevated FSH is the most evident endocrine abnormality levels have circadian fluctuations, particularly marked in in infertile men, particularly in cases of nonobstructive younger men, where there is a striking difference in testos­ azoospermia (NOA) and severe oligozoospermia. High terone levels measured in early morning versus those 67 Section 2 Male Factor Infertility

taken later in the day. The mean maximum level of so that peak results can be compared with the usual 720 ng/dl (25 nmol/l) is reached at approximately 8 standards. In general, because of this circadian variations AM, and declines to a mean minimum of 432 ng/dl (15 in secretion, serum samples for total testosterone deter­ nmol/l) at approximately 10 PM. However, such degree mination should be obtained between 7:00 AM and 9.00 of change between morning and evening testosterone AM.34 Moreover, because of diurnal variation in testos­ levels is less striking in older men. Nevertheless, it is best terone and pulsatile pattern of secretion of LH and FSH, in all cases to measure the concentration in the morning an alternative is to perform hormone assays on three pooled blood samples taken at 10 minutes intervals.35 In men who are found to have azoospermia but Factors that affect circulating sex Table 3 normal testosterone, LH, and FSH levels and normal hormone-binding globulin levels testes volume, obstructive disorders should be ruled Increase Decrease out by measuring seminal levels of fructose and neutral Aging Prepubertal development α-glucosidase. The latter originates in the epididymis.25 Growth hormone deficiency Obesity In case of azoospermia or severe oligospermia, normal Estrogens Hyperinsulinemia testosterone and LH levels, but elevated FSH, primary Androgen deficiency Glucocorticoids spermatogenic failure should be considered. These Hyperthyroidism Androgens patients should get testicular volume assessment, karyo­ Hepatitis Progestins typing and Yq micro deletion screening. Hypothyroidism Primary testicular failure (spermatogenesis and ster­ Growth hormone excess Familial oidogenesis) often presents with low testosterone, and elevated FSH and LH serum levels; whereas, patients

68 Figure 7 Nomogram for calculating free testosterone (CFT) from total testosterone (TT) and (SHBG) Source: Carruthers M. Androgen deficiency in the adult male: causes, diagnosis and treatment. London: Taylor & Francis; 200493 Chapter 4 Hormonal Management of Male Infertility with selective spermatogenic failure have normal testos­ Serum estradiol determination may be considered in terone and LH, and only elevated FSH. In cases with low select group of patients, such as ones with Klinefelter’s testosterone and low or inappropriately normal LH and syndrome and in cases with gynecomastia, a testicular FSH, it is important to determine PRL, cortisol, serum mass, a history consistent with exogenous estrogen ferritin, TSH and free thyroxine levels. These patients may exposure, or evidence of androgen resistance.38 need magnetic brain resonance imaging to determine the cause of HH. Normal MRI, PRL level and other measure­ ments in these men point out to the possibility of hypo­ DISEASES OF THE HPG AXIS thalamic disorders, such as anosmicHH (Kallmann’s syndrome), nonanosmic isolated hypogonadotropic Hypothalamic and Pituitary Disorders hyp-ogonadism (IHH) and adult onset HH. Direct meas­ Hypogonadotropic hypogonadism results from failure urement of GnRH is not feasible in humans due to pulsa­ of the hypothalamus or pituitary to stimulate and main­ tile mode of secretion, short half-life, very low concentra­ tain normal gonadal function.39 Pituitary functions may tion and dilution of this hypothalamic hormone by the be affected in events of pituitary tumors, infarction, pituitary portal circulation and then by systemic circula­ inflammatory and granulomatous diseases, surgery and tion. In unresolved cases when there is low or normal radiation. However, gonadotropin deficiency may also LH and FSH, GnRH stimulation test can be conducted. occur in the presence of otherwise normal pituitary func­ Subcutaneous injection of intravenous 100 µg of GnRH tion when the secretion or action of GnRH is altered: IHH should normally cause a three fold rise in LH and 1.5 times in FSH after 30–45 minutes of injection. The Isolated Hypogonadotropic Hypogonadism rise in LH/FSH helps confirm the diagnosis of anosmic Isolated hypogonadotropic hypogonadism is clinically and normosmic HH.32 In contrast, negative response is defined as absent or incomplete puberty by the age of usually attributed to failure of pituitary gland to respond 18 years because of low gonadotropin secretion. The to the injected GnRH. Such unresponsiveness may occur GnRH deficiency can be due to impaired migration of the due to lack of previous exposure to GnRH (Priming GnRH neurons to the hypothalamus during embryo­nic effect) or due to mutated gene coding for GnRH receptor development, abnormal maturation or decreased (GNRHR). To discriminate between the two conditions, survival of GnRH neurons, or resistance to the action of subcutaneous portable GnRH pump releasing 5 µg of GnRH at the level of pituitary. IHH can be either sporadic GnRH every (90–120) is undertaken for 36 hours a day or familial. It may be inherited in an X-linked recessive, for 7 days. Then GnRH stimulation test is repeated. autosomal dominant or autosomal recessive mode. Positive rise confirm the HH diagnosis and exclude the However, the genetics are not strictly Mendelian. IHH possibility of pituitary unresponsiveness.32 may be due to mutations in more than one gene, as well Normal PRL level in men is usually less than 18 ng/dl as interaction between genes, or between genes and envi­ (550 mIU/l). However, due to high assay variability, ronmental factors.40 In males, the prevalence is around testing should be repeated, if levels are elevated. If 1 in 10,000. There are two forms of IHH depending on hyperprolactinemia is discovered and secondary causes the presence or absence of the normal sense of smell: are ruled out or PRL levels are above 150 ng/dl, a gado­ normosmic IHH and Kallmann’s syndrome. linium enhanced MRI with special attention to the region of hypothalamus and pituitary is indicated for revealing Kallmann’s Syndrome a prolactinoma or another space occupying process. It is a form of IHH associated with olfactory disturbances Both in complete and partial forms of androgen insen­ (hypo- or anosmia) due to the absence or hypoplasia of sitivity, serum testosterone and LH levels are usually the olfactory bulbs and tract. The incidence is estimated elevated, but FSH may be normal or elevated. Estradiol is to be about 3.7% of all IHH male patients. The male higher than in normal males. Failure of SHBG to decrease preponderance of cases remains still unexplained. The after testosterone administration confirms the androgen olfactory and reproductive deficits are combined with insensitivity. An hCG stimulating test demonstrating various defects, including cryptorchidism, bimanual normal testosterone and DHT production can be used synkinesis (mirror movements), unilateral renal agen­ to distinguish partial androgen insensitivity syndrome esis, craniofacial or dental abnormalities, syndactyly, from defects in testosterone biosynthesis and 5-α reduc­ sensorineural deafness.41 tase activity.36,37 Karyotyping reveals 46 XY and is indi­ cated especially in cases with ambiguous genitalia and Hyperprolactinemia bilateral inguinal hernias. Androgen receptor studies are It is another endocrine cause of secondary hypogonadism helpful in cases with incomplete insensitivity. commonly seen in clinical practice. PRL is an anterior 69 Section 2 Male Factor Infertility

pituitary hormone whose excessive concentrations the phenotype and reproduction. A number of genetic suppress the secretion of FSH and LH and/or impede disorders, such as Klinefelter’s syndrome and Y chromo­ their action on the gonads. Hyperprolactinemia can be some microdeletions, have been implicated in spermato­ caused by prolactinomas, pituitary tumors secreting genic failure. Table 4 demonstrates causes of HH. both PRL and GH, processes causing pituitary stalk compression or section, empty sella syndrome, medi­ Disorders of Androgen Actions cations, primary hypothyroidism, chronic renal failure Androgen insensitivity causes undermasculinization of among other causes or may be idiopathic. Symptoms various degrees in 46 XY individuals. The androgen include depressed libido, erectile dysfunction, and infer­ receptor gene is located on the X chromosome between tility. Galactorrhea is rare in men. Xq11 and Xq13. Androgen insensitivity syndromes result from defects in androgen receptor number or func­ Isolated FSH and LH Deficiency tion. Androgen insensitivity may be complete or partial Rare disorders include isolated FSH deficiency, which (incomplete). Complete androgen insensitivity syndrome may present with oligo- or azoospermia, though (testicular feminization syndrome) is characterized by such patients have normal virilization and normal complete feminization of genetic males. Partial androgen testosterone and LH levels.42 Isolated LH deficiency insensitivity presents with great variations from normal (Pasqualini syndrome, fertile eunuch syndrome) on the male phenotype with infertility to individuals with other hand leads to eunuchoid habitus, low testosterone genital ambiguity and gynecomastia.36,37 levels, but normal maturation of germinal epithelium with Leydig cell atrophy on testicular biopsy. Serum levels of LH are low, but of FSH are normal.32 DISEASES OF THE ADRENAL GLANDS

Other Complex Congenital Syndrome Glucocorticoid excess (hypercortisolism) in Cushing’s This syndrome associated with HH includes Prader- syndrome of either endogenous or exogenous etiology Willi syndrome where lack of GnRH secretion leads to may also suppress LH secretion and testosterone LH and FSH deficiency. The hypogonadism in the very bio­syn­thesis resulting in testosterone deficiency and rare genetic disorders, Laurence-Moon syndrome and hypo­spermatogenesis. Bardet-Biedl syndrome, is not obligate.32 Androgen excess can induce a hypogonadal state by inhibiting gonadotropin production through nega­ Testicular Diseases tive feedback. The source of androgen excess could be Hypergonadotropic Hypogonadism either endogenous production from adrenals or testes, This group includes different congenital and acquired or exogenous anabolic steroids. Deficiency of enzyme disorders primarily affecting the gonads (Table 3). 21-hydroxylase is the commonest cause of congenital The result in testicular failure and infertility, but some adrenal hyperplasia. The excess of adrenal androgens in of them can cause only fertility disturbances without this condition may lead to precocious pseudo-puberty obvious signs of hypogonadism. Defects in androgen and infertility. It can be diagnosed by high basal and production, as well as conversion of testosterone to DHT ACTH stimulated plasma 17-α hydroxyprogesterone due to the deficiency of enzyme 5-α reductase, affect levels. Men with partial enzyme deficiency may remain undiagnosed until late in adulthood, though they are usually fertile. ‘Adrenal or testicular Leydig cell tumors’ Disorders causing primary or can also produce excess serum androgens and require Table 4 hypergonadotropic hypogonadism radiological imaging for diagnosis. • Klinefelter’s syndrome (47,XXY) • XX male syndrome • 47,XYY men THYROID DISORDERS • Gonadal dysgenesis • Noonan’s syndrome Both hyper- and hypothyroidism may have an adverse • Defects in androgen biosynthesis impact on male fertility. Hyperthyroidism is known to • Bilateral anorchia (vanishing testes syndrome) cause elevation of SHBG and decline in semen quality • Acquired anorchy especially in semen motility.43 In literature, hyperthy­ • Orchitis roid men has shown relative primary gonadal insuffi­ • Varicocele ciency that might be due to exaggerated SHBG levels 70 • Adult seminiferous tubule failure and increased gonadotropin levels with co-pulsatility Chapter 4 Hormonal Management of Male Infertility between LH and FSH, which was more pronounced HORMONAL INTERVENTION IN 44 than in healthy men. Evidence is weak though about MALE INFERTILITY the possible deleterious effects of hypothyroidism on male reproductive system.45 Hormonal therapy was utilized in the field of male infer­ tility many years ago; however, the fertility outcomes confront a great deal of disappointment and frustration. EXCESS ESTROGEN Alternatively, the successful conception rates achieved through assisted reproductive technology has led to Estrogen excess can also produce secondary testicular infrequent and unenthusiastic demand on hormonal failure by inhibiting pituitary gonadotropins. It can be intervention. Nevertheless, appropriately prescribed derived from either estrogen secreting adrenal or testic­ hormonal treatment is cost-effective and attractive ular tumors or excess peripheral conversion of andro­ mode of therapy. Currently, therapeutic and fertility gens to estrogens by aromatase enzyme in patients preservation roles are the two main sorts of hormonal suffering from chronic liver diseases or obesity. Men manipulation. with high estrogen levels may present with gyneco­ Therapeutic intervention aiming at restoring the mastia, erectile dysfunction and testicular atrophy. fertility potential is used for specific replacement of a particularly deficient hormone, or used in nonspecific manner in idiopathic male infertility with no identifi­ DIABETES MELLITUS AND able endocrine abnormalities. METABOLIC SYNDROME Adequate replacement therapy either with GnRH or LH and FSH can induce spermatogenesis in patients Diabetes mellitus affects the reproductive function with HH. Maturation of the human sperm takes mainly through microangiopathy and neuropathy, approximately 72 days,48 so the treatment should last at which in turn leads to erectile dysfunction and ejacu­ least 3 months for the sperm to appear in the ejaculate. late disturbances. Obesity as well as diabetes mellitus Usually a much longer period (up to 2 years or even type 2 (DM 2) may cause hypogonadism and infer­ more) is required, especially in congenital HH. tility. Both low and high body mass index (BMI) are associated with disturbances in spermatogenesis. In Gonadotropin Releasing Hormone obesity, increased peripheral conversion of andro­ Rationale: GnRH stimulates anterior pituitary to secrete gens to estrogens in excess peripheral adipose tissue LH and FSH which in turn regulates T cells produc­ suppresses the gonadotropin secretion. Another unfa­ tion and spermatogenesis. It can thus be used in pulsa­ vorable effect of obesity may be the oxidative stress tile fashion in men with HH caused by hypothalamic leading to impaired spermatogenesis.46 Dyslipidemia dysfunction, but not in those having loss of pituitary also increases oxidative stress. Metabolic syndrome is function. It can also be used for induction of puberty. not a separate disease by itself but a cluster of abnor­ malities, including visceral type obesity, dyslipidemia, Method of administration: GnRH is administered using hypertension and impaired glucose metabolism or portable pump in doses of 4–20 µg per pulse adminis­ DM 2 with insulin resistance as the hypothesized tered subcutaneously every 2 hours as pulsatile therapy. underlying pathogenic mechanism. An association of Doses are adjusted until serum testosterone reaches metabolic syndrome with low testosterone and low mid-normal levels. GnRH as nasal spray is used for SHBG serum levels is widely accepted, but the cause treatment of cryptorchidism. and effect relationship is still unclear. Men with low testosterone and low SHBG levels are more likely to Indications: GnRH has been demonstrated to be quite develop insulin resistance and DM 2. On the other effective in inducing androgenization and spermato­ hand, insulin is known to inhibit SHBG synthesis, genesis in men with IHH.49-51 It did not differ in effi­ therefore in insulin-resistant individuals SHBG, and cacy in terms of spermatogenesis and pregnancy rates consequently total testosterone is decreased. A nega­ as compared to the gonadotropin therapy. In prelimi­ tive correlation of total testosterone with insulin levels, nary investigations involving infertile men who had insulin resistance and BMI in young males with meta­ cryptorchidism, GnRH analogues have been shown to bolic syndrome was reported.47 improve spermatogenesis when used as an adjunct to

71 Section 2 Male Factor Infertility

orchidopexy.52,53 On the basis of successful treatment that FSH is necessary for maintenance of quantitatively of one single case Iwamoto et al. concluded54 that nasal normal spermatogenesis.56 therapy with GnRH analogue buserelin in low doses avoids pituitary down-regulation exerting stimulatory Indications: Several studies although not placebo effect on it and therefore may be an effective and well- controlled have shown induction of spermatogenesis and tolerated therapeutic option for patients with HH of ability to induce pregnancy with use of mixed gonado­ hypothalamic origin.54 tropin therapy51,57,58 and it is presently the most widely used therapy for hypogonadotropic infertility. Testicular Side effects and disadvantages: Wearing of the portable volumes of 8 ml or more and post-pubertal onset of pump is cumbersome and hence discouraging for gonadotropin deficiency are more likely to respond than patients. Formation of anti-GnRH antibodies in certain those with testicular volumes of less than 4 ml and pre- cases has also raised some concern.55 Furthermore, pubertal onset.50 Nevertheless, this treatment is also indi­ at present consensus exists that GnRH has no role as cated in cases with cryptorchidism or with small testic­ empiric therapy in idiopathic infertility. ular volume.49 According to a recent study men with BMI less than 30 kg/m2 have a greater chance of achieving Gonadotropins spermatogenesis than men with a BMI equal to or greater Various urinary, purified, and recombinant forms of than 30 kg/m2.39 Low BMI and advanced sexual matu­ gonadotropins have been used including hCG with LH rity, especially large baseline mean testicular volume activity, human menopausal gonadotropin [(hMG) FSH are predictors of a good response to combined therapy analogue], recombinant FSH and LH. with recombinant human FSH and hCG.39 Recent obser­ vations has demonstrated useful effect of hCG therapy Mixed Gonadotropin Therapy in improvement of sperm retrieval rates in men with Rationale: In all forms of hypogonadism testosteroneal Klinefelter’s syndrome as will be described later. one is sufficient for maturation and maintenance of secondary sex characteristics, libido and erectile func­ Side effects and disadvantages: Although spermatogenesis tion. In HH; however, the anterior pituitary hormones is induced in the majority of cases, some patients may LH and FSH are required together to initiate and not respond. For quantitatively, normal spermatogen­ maintain spermatogenesis. A combined gonadotropin esis both gonadotropins are required. The treatments therapy can thus be used to treat hypogonadotropic with gonadotropins and GnRH are expensive, there­ infertility arising at the level of pituitary or hypothal­ fore, they should be introduced only when a desire for amus including IHH, when treatment with GnRH is not children is present or once to stimulate testicular func­ desired or indicated. hCG is used as the source of LH tion until induction of spermatogenesis is achieved activity to stimulate testosterone secretion by Leydig before switching to a long lasting substitution therapy cells, whereas hMG acts as FSH.56 In recent years, recom­ with testosterone.59 binant gonadotropins have been introduced in clinical practice. FSH Monotherapy Rationale: FSH has an established role in promoting sper­ Method of administration: The therapy is started with hCG matogenesis. It enhances the production of androgen- 1,000–2,500 IU two times/week subcutaneously or intra­ binding protein by Sertoli cells which are required to muscularly; adjusting the dose to target mid-normal maintain high local concentration of testosterone in the testosterone levels. Testosterone levels are measured seminiferous tubules thus supporting spermatogen­ 48 hours after the hCG injection. Alternatively, recom­ esis.60 However, the role of FSH in the maintenance of binant LH can be used. After a period of 8–12 weeks of spermatogenesis remains controversial.56 hCG or recombinant human LH therapy, a highly purified hMG or recombinant human FSH is added at the Method of administration: Purified or recombinant human doses of 150–225 IU three times/week subcutaneously.22 FSH is given at doses ranging from 50 IUto 300 IU The treatment continues until sperm appear in the ejacu­ administered subcutaneously threetimes weekly for late or pregnancy occurs respectively, but in some cases over 3 months. therapy may be required for 1–2 or more years. As soon as in men with HH spermatogenesis is Indications: Several randomized controlled trials have induced with combined gonadotropin treatment or with evaluated the efficacy of FSH in men with idiopathic GnRH, it can be maintained qualitatively by hCG alone infertility with mixed results.61,62 In these studies, 72 for long time, but the decreasing sperm counts indicate the gonadotrophic status of the patients was not well Chapter 4 Hormonal Management of Male Infertility characterized. Although pregnancy outcomes were Indication: Cochrane meta-analysis of 10 randomized not reported in most of these studies, improvement in controlled trials with idiopathic infertility found no sperm parameters was noted in some when FSH was improvement in pregnancy rates with anti-estrogen used at higher doses.48,63 When used 50 days before therapy.67 Similarly, another meta-analysis reported no ICSI, FSH has been shown to improve fertilization, significant change in pregnancy outcomes with clomi­ implantation and pregnancy rates in men with severe phene citrate or tamoxifen therapy of idiopathic infer­ oligozoospermia.64 tile men (OR, 1.54; 95% CI: 0.99-2.40).65 However, some studies demonstrated improvement in sperm count and Side effects and disadvantages: Evidence is weak and the sperm motility.68 Hence, empiric therapy for at least consensus is that FSH therapy alone has at the best little 3 months may have a beneficial effect on fertility status efficacy in treating idiopathic male infertility. in subfertile men by improving semen parameters which may allow a down-staging of the required ART proce­ Androgen Therapy dure, i.e. utilizing intrauterine insemination instead of Testosterone Therapy ICSI. Recent reports have shown specific indication and Rationale: Although testosterone has contraceptive beneficial effect of clomiphene citrate and its isomer properties in men due to its negative feedback on hypo­ enclomiphene in treatment of men with HH and resto­ thalamic-pituitary axis and thus inhibition of LH and ration of physiological level of testosterone. Clomiphene FSH, and spermatogenesis respectively. It has been tried citrate can also restore testosterone/estrogen ratio in to treat subfertile men with testosterone based on two hypogonadal men.69,70-72 Lastly, men with Klinefelter’s rationales. Raising serum testosterone would improve syndrome who have been prescribed clomiphene citrate epididymal maturation of spermatozoa; gonadotro­ show an improvement in sperm retrieval rates by testi­ pins and sperm concentration respectively increase cular extraction as demonstrated below. transiently upon sudden stopping of testosterone, the so-called ‘rebound effect’. Side effects and disadvantages: Literature support remains inconclusive awaiting large randomized prospective Method of administration: Male infertility is treated using trials of empiric therapy in idiopathic male infertility. testosterone undecanoate or mesterolone in doses of Unfortunately, deterioration in semen parameters of 120–240 mg/day and 75–150 mg/day respectively. some men with idiopathic male infertility has been reported after using clomiphene citrate. For replace­ Indication: Various meta-analyses have demonstrated ment of testosterone in men with HH, two regimens no improvement in pregnancy outcomes with androgen have been described either low dose daily regimen of therapy in idiopathic male infertility.65,66 25 mg69or 50 mg given three times a week.71

Side effects and disadvantages: Published literature Tamoxifen and Testosterone strongly discourages any role of testosterone mono­ Combination Therapy therapy for men with idiopathic infertility. Rationale: Tamoxifen has been shown to primarily increase sperm density without much improve­ Anti-estrogen Therapy ment in other parameters, such as sperm motility and Anti-estrogen Monotherapy morphology. One of the main reasons could be infe­ Rationale:Anti-estrogens indirectly stimulate the secre­ rior androgenic environment in the reproductive tract tion of GnRH, FSH and LH by binding to ERα in the of oligozoospermic men. This in turn may compromise hypothalamus and pituitary, thereby blocking estrogen epididymal maturation of the spermatozoa which can feedback inhibition. The resultant increase of gonado­ be theoretically overcome by supplementing tamoxifen tropin concentration is believed to improve the game­ treatment with testosterone. togenic function of the testes. Method of administration: Tamoxifen and testosterone Method of administration: The two most commonly used undecanoate are administered as 20 mg and 120 mg nonsteroidal anti-estrogens are clomiphene citrate and respectively in daily divided doses for 6 months. tamoxifen. Clomiphene citrate is usually prescribed in doses of 12.5–50 mg/day either continuously or on a Indication: Treatment with tamoxifen and testosterone 25-day cycle with a 5-day rest period, each month for undecanoate improved sperm variables and led to a 3-6 months. Tamoxifen is administered at a dosage of higher incidence of pregnancy in couples with subfer­ 10–20 mg daily over a period of 3–6 months. tility related to idiopathic oligozoospermia.73 73 Section 2 Male Factor Infertility

Side effects and disadvantages: Literature is scarce and in semen parameters.76 Normal spermatogenesis primarily restricted to single group of investigators. proven by testis biopsy was achieved with letrozole in one case with azoospermia and normal FSH serum Tamoxifen and Kallikrein Combination Therapy levels.75 Controlled studies evaluating the efficacy Rationale: While tamoxifen improves sperm count, of aromatase inhibitors on pregnancy outcomes are kallikrein has been shown to improve sperm motility; still lacking. Furthermore, Ramasamy et al. (2009) hence a combination can hypothetically be useful in indicated that medications leading to physiological men with idiopathic oligoasthenozoospermia. endogenous testosterone secretion, such as aromatase inhibitors, clomiphene or hCG result in a better chance Method of administration: Tamoxifen is administered as of sperm retrieval in men with Klinefelter’s syndrome 20 mg/day along with 600 IU of kallikrein daily for with either normal or low baseline testosterone than 3 months. those Klinefelter’s men who used exogenous testos­ terone to induce secondary sexual characteristics Indication: Improvement in both sperm count and [(77% vs. 55%)77 Level C evidence]. Such observation motility with such a therapy has been demonstrated in may be attributed to exogenous testosterone induced few trials when used in idiopathic normogonadotropic suppression of release of pituitary FSH and LH and men with oligoasthenospermia.74 henceforth suppression of spermatogenesis.

Side effects and disadvantages: Pregnancy outcomes have Side effects and disadvantages: Further investigation is not yet been studied and further studies are warranted needed before drawing any conclusions on the use of to draw any inferences. aromatase inhibitors in male infertility. Elevation of hepatic enzymes has been reported with both these Therapy with Aromatase Inhibitors drugs and hence caution is advised in those who have Rationale: Aromatase is a P450 cytochrome enzyme underlying liver disease. that converts androgens to estrogens. Aromatase inhibitors block its activity thereby reducing serum Growth Hormone Therapy estradiol concentration and its negative feedback on Rationale: GH acts on gonads directly or through hepatic the hypothalamus and pituitary, resulting in elevated secreted insulin-like growth factor-1 and plays a signifi­ serum FSH levels, which in turn, might improve cant role in sexual growth and differentiation, gonadal spermatogenesis.75 On the other hand, aromatase steroidogenesis and gametogenesis.78 inhibitors lead to increase in testosterone which also might contribute to achievement of fertility. Method of administration: Recombinant GH is given for 12 weeks. Method of administration: Two types of aromatase inhi­ bitors are available, steroidal (e.g. testolactone) and Indication: GH therapy has shown mixed results in nonsteroidal (letrozole and anastrozole). The latter is terms of improvement in sperm parameters and preg­ more effective in increasing testosterone to estrogen nancy rate when used in oligo- and asthenozoospermic ratio and is less likely to cause interruption of the men.79,80 When used as an adjunct therapy in a small adrenal axis beyond aromatase inhibition. Testolactone study of seven men with HH who failed gonadotropin is given in doses of 100–200 mg/day, whereas anastro­ therapy, GH has been demonstrated to help induce zole is used as 1 mg/day dosage and letrozole 2.5 mg spermatogenesis.81 daily orally for 4–6 months. Side effects and disadvantages: Available literature is Indication: Hyperestrogenemia associated with male limited and further studies trying combination therapy infertility constitutes the main indication for the use of of GH and gonadotropins for male infertility are aromatase inhibitors therapy. Elevated estrogen level awaited. or elevated estrogen to testosterone ratio is obviously observed in men with significant obesity associated Oxytocin Therapy with idiopathic HH and Klinefelter’s syndrome. Rationale: Oxytocin has been shown to promote sperm In idiopathic oligozoospermic men studied in progression through the reproductive tract by improving double blind randomized controlled fashion, testo­ epididymal contractility. It can thus be used to increase lactone therapy failed to show any improvement sperm retrieval in men with oligozoospermia. 74 Chapter 4 Hormonal Management of Male Infertility

Method of administration: Oxytocin is given as intrave­ these, more than 3,000 patients receive treatment, such nous injections or intranasal just before ejaculation. as alkylating agents, platinum based chemotherapy or radiation which may render men azoospermic or severe Indication: Oxytocin therapy has failed to improve sperm oligozoospermic.84,85 Cytotoxic chemotherapy may also output in severely oligozoospermic men.82 be used in the treatment of autoimmune diseases. The mechanisms of deranged spermatogenesis include direct Side effects and disadvantages: This form of therapy lacks stem cell aplasia or failure of differentiation of surviving evidence in supporting any role in male infertility. stem cells into mature sperm. Restoration of male fertility is very slow and may take upto 6 years. Endocrine alter­ Endocrine Therapy for Hyperprolactinemia ations, described in these men, particularly with germ Dopamine agonists are the primary therapy for both cell aplasia, may include a decreased level of serum micro- and macroadenomas associated hyperprol­ inhibin and consequently elevated serum FSH level. actinemias, as well as for non-tumor related hyperpro­ Chemotherapy or radiotherapy induced testicular lactinemia. Historically, bromocriptine (2.5–10.0 mg, ischemia contributes to decline in the systemic distri­ maximal 30 mg a day) was the first effective medical bution of testosterone, elevated LH level and increased therapy. Cabergoline, a non-ergot DA agonist, is admin­ intratesticular testosterone.86,87 Ultimately, successful istered at a dosage of 0.25–1.0 mg twice per week. Both resumption of spermatogenesis depends on survival of normalize PRL levels, decrease tumor size and restore stem cells and their ability to differentiate into sperm. reproductive function. Cabergoline is better tolerated Various hormonal regimens have been used for than bromocriptine. However, there are some recent protection of testicular tissues during chemo- or radio­ concerns of heart valvular defects with higher doses of therapy. In animals, GnRH, FSH and steroids were cabergoline.83 administered, whereas in humans GnRH agonists alone or in combination with testosterone or antiandrogen, Summary: Therapy for subfertile men generally falls under testosterone and medroxyprogesterone have been used two categories: specific and empiric, depending upon with mixed results. Animal studies have shown protec­ the etiology. Endocrine evaluation of men presenting tive effect of GnRH given for several weeks (upto 6 with infertility should aim at identifying candidates for weeks) before cytotoxic chemotherapy and continued specific therapy. For men who have HH, both gonado­ thereafter or through administration of GnRH after tropin therapy and pulsatile GnRH are equally effec­ irradiation or chemotherapy to stimulate spermato­ tive. However, idiopathic infertility which is a much genesis.86,88 Only single small study out of seven trials more frequently encountered clinical problem responds in humans has shown such promising improvement by poorly to empiric endocrine treatment. Recently, several the use of testosterone, concomitantly with cyclophos­ hormonal intervention studies have shown promise in phamide for the treatment of autoimmune nephritis.89 management of idiopathic male infertility. Further trials Nevertheless, further studies are actually required and with adequate sample size and study design are warranted prolonged pretreatment with hormonal therapy for before it can be put into routine clinical practice. extended period of time for several weeks should be utilized to show a protective effect. Other options for fertility preservation encompass CYTOPROTECTIVE HORMONAL EFFECTS sperm or testicular tissue cryopreservation. The trans­ ON SPERM IN CANCER PATIENTS plantation of cryopreserved spermatogonia is being studied and preliminary animal studies have shown Hormonal manipulation inducing a state of quiescence beneficial effects of GnRH analogues in maintenance of may protect the testicular germ cells from being heavily the survival of transplanted spermatogonia.90,91 damaged by exposure to gonadotoxins, such as cancer chemotherapy, or radiotherapy. This theory stems from the observation of relative resistance of prepubertal REFERENCES testes to cancer chemotherapy and animal studies in which GnRH agonists or antagonists were given to 1. Guyton AC, Hall JA. Endocrinology and Reproduction. suppress spermatogenesis. In: Guyton AC, Hall JA (Eds). Text book of Medical In United States 17,000 men in reproductive ages Physiology, 11th edition. Philadelphia, Pennsylvania: between 15 years and 45 years are diagnosed with Elsevier Saunders; 2006. pp.905-17. cancer, such as Hodgkin’s lymphoma, leukemia, testic­ 2. Brook CG, Rosalind SB. The application of science ular cancer and soft tissue sarcoma each year.84,85 Of to clinical practice. In: Brook CG, Brown RS (Eds). 75 Section 2 Male Factor Infertility

Handbook of Clinical Pediatric Endocrinology, 1st impairment of spermatogenic efficiency with increasing edition. Massachusetts, USA: Blackwell Publishing, Inc; obstructive interval. Fertil Steril. 2004;81:1595-03. 2008. pp. 1-13. 19. Bhasin S, Fielder TJ, Swerdloff RS. Testosterone selec­ 3. Daniel PM, Treip CS. The pathology of the hypotha­ tively increases serum follicle-stimulating hormone lamus. J Clin Endocrinol Metab. 1977; 6:3-19. (FSH) but not luteinizing hormone (LH) in gonado­ 4. Daniel PM, Prichard MML. Studies of the hypothalamus tropin-releasing hormone antagonist-treated male rats. and the pituitary gland. Acta Endocrinologica. 1975 Evidence for differential regulation of LH and FSH 80:1-216. secretion. BiolReprod. 1987; 37(1):55-9. 5. Brodal P. The central autonomic system: the hypothal­ 20. Dufourny L, Caraty A, Clarke IJ, et al. Progesterone- amus. In: Brodal P(Ed). The Central Nervous System receptive dopaminergic and neuropeptides Y neurons Structure and Function, 4th edition. Oxford: Oxford project from the arcuate nucleus to gonadotropin- University Press; 2010. pp. 440-58. releasing hormone-rich regions of the ovine preoptric 6. Knobil E. The GnRH pulse generator. Am area. Neuroendocrinology. 2005; 82:21–31. J Obstet Gynecol. 1990; 163:1721-7. 21. Krsmanovic LZ, Hu L, Leung PK, et al. The hypotha­ 7. Martinez de la, Escalera G, Choi ALH, et al. Generation lamic GnRH pulse generator: multiple regulatory mech­ and synchronization of gonadotropin releasing hormone anisms. Trends Endocrinol Metab.2009; 20:402-8. (GnRH) pulses: intrinsic properties of the gt1-1 gonado­ 22. Bhasin S. Approach to the infertile man. J Clin Endocrinol tropin releasing hormone (GnRH) neuronal cell line. Metab. 2007; 92(6):1995-2004. Proc Natl Acad Sci USA. 1992;89:1852-5. 23. Dunkel L. Normal and Delayed Puberty. In: Winters 8. Styne DM, Grumbach MM. Puberty: ontogeny, neuroen­ SJ (Ed). Male Hypogonadism, basic, clinical and thera­ docrinology, physiology, and disorders. In: Kronenberg peutic principles. New Jersey USA: Humana Press HM, Melmed S, PolonskyKS, LarsenPR(Eds). Williams Inc.;2004. pp.3-79. Textbook of Endocrinology, 11th edition. Philadelphia 24. Sedlmeyer IL; Palmert MR. Delayed puberty: anal­ USA: Elsevier Inc.; 2008.pp.969-1166. ysis of a large case series from an academic center. 9. Low MJ. Neuroendocrinology. In: Kronenber HM, J ClinEndocrinolMetab. 2002;87(4):1613-20. Melmed S, Polonsky KS, Larsen PR (Eds). Kronenberg 25. WHO laboratory manual for the examination and And Williams Textbook of Endocrinology, 11th edition. processing of human semen, 5th edition. WHO, Geneva. Philadelphia PA: Saunders; 2008. pp.85-135. 2010. 10. Melmed S, Kleinberg D. Anterior pituitary. In: 26. Sigman M, Lipshultz LI, Howards SS. Evaluation of Kronenberg HM, Melmed S, Polonsky KS(Eds). Williams the subfertile male. In: Lipshultz LI, Howards SS(Eds). Textbook of Endocrinology, 11th edition. Pennsylvania: Infertility in the Male, 3rd edition. St. Louis: Mosby; 1997. Saunders Elsevier; 2008. pp. 240-42. 27. American Urological Association. The optimal evalu­ 11. Horvath E, Kovacs K. Fine structural cytology of the ation of the infertile male [online]. Available from adenohypophysis in rat and man. J Electron Microsc http://www.auanet.org/content/media/optimal Tech. 1988; 8:401-32. evaluation[Accsessed 2010]. 12. Andersen CY, Westergaard LG, van Wely M. FSH 28. Turek P. Male infertility. In: TanaghoS, McAninchJW isoform composition of commercial gonadotrophin (Eds). Smith’s General Urology, 17th edition. 2008. preparations: a neglected aspect? Reprod Biomed pp. 684-716. Online. 2004; 9(2):231-6. 29. Bergmann M, Behre HM, Nieschlag E. Serum FSH 13. Fares F. The role of O-linked and N-linked oligosac­ and testicular morphology in male infertility. Clin charides on the structure-function of glycoprotein Endocrinol (Oxf). 1994;40:133-6. hormones: development of agonists and antagonists. 30. Vernaeve V, Tournaye H, Schiettecatte J, et al. Serum Biochim Biophys Acta. 2006; 1760:560-7. inhibin B cannot predict testicular sperm retrieval 14. Vermeulen A. Androgens in aging male. J Clin in patients with non-obstructive azoospermia. Hum Endocrinol Metab. 1991; 73:221-4. Reprod. 2002;17(4):971-6. 15. Bremner W, Vitiello V, Prinz P. Loss of circadian rhyth­ 31. Kumanov P, Nandipati K, Tomova A, et al. Inhibin B is a micity in blood testosterone levels with aging in normal better marker of spermatogenesis than other hormones men. J Clin Endocrinol Metab. 1983; 56:1278-81. in the evaluation of male factor infertility. Fertil Steril. 16. Handelsman DJ. Ageing in the hypothalamic–pitui­ 2006;86(2):332-8. tary–testicular axis. In: Neil JD (Ed). Knobil and Neill’s 32. Simoni M, Nieschlag E Nieschlag. Endocrine laboratory Physiology. 2008; 2697-2759. diagnosis. In: E, Behre HM, Nieschlag S (Eds). Andrology, 17. Weinbauer GF, Luetjens CM, Simoni M, et al. 3rd edition. Heidelberg: Springer; 2009. pp. 109-18. Physiology of testicular function. In: Nieschlag E, Behre 33. Vermeulen A, Verdonck L, Kaufman JM. A critical HM, Nieschlag S (Eds). Andrology, Male Reproductive evaluation of simple methods for the estimation of Health and Dysfunction, 3rd edition. Berlin Heidelberg: free testosterone in serum. J Clin Endocrinol Metab. Springer-Verlag; 2010. pp. 11-59. 1999;84:3666-72. 18. Raleigh D, O’Donnell L, Southwick GJ, et al. Stereological 34. Wang C, Nieschlag E, Swerdloff R, et al. Investigation, 76 analysis of the human testis after vasectomy indicates treatment, and monitoring of late-onset hypogonadism Chapter 4 Hormonal Management of Male Infertility

in males: ISA, ISSAM, EAU, EAA, and ASA recommen­ with isolated hypogonadotropic hypogonadism. dations. European Urology. 2009;55:121-30. J Clin Endocrinol Metab. 1988;67(6):1140-5. 35. Bain J, Langevin R, D’Costa M, et al. Serum pituitary and 51. Kliesch S, Behre HM, Nieschlag E. High efficacy of gonad­ steroid hormone levels in the adult male: one value is as otropin or pulsatile gonadotropin releasing hormone good as the mean of three. FertilSteril. 1988;49:123-6. treatment in hypogonadotropic hypogonadalmen. Eur 36. Balducci R, Ghirri P, Brown TR, et al. A clinician looks at J Endocrinol. 1994;131(4):347-54. androgen resistance. Steroids. 1996;61(4):205-11. 52. Hadziselimović F, Herzog B. Treatment with a lutei­ 37. Yong EL, Loy CJ, Sim KS. Androgen receptor gene and nizing hormone-releasing hormone analogue after male infertility. Hum Reprod Update. 2003;9(1):1-7. successful orchiopexy markedly improves the chance of 38. Sokol RZ. Endocrinology of male infertility: evaluation fertility later in life. J Urol. 1997;158(3 Pt 2):1193-5. and treatment. Semin Reprod Med. 2009;27(2):149-58. 53. Huff DS, Snyder HM, Rusnack SL, et al. Hormonal 39. Warne DW, Decosterd G, Okada H. A combined anal­ therapy for the subfertility of cryptorchidism. Horm ysis of data to identify predictive factors for spermato­ Res. 2001;55(1):38-40. genesis in men with hypogonadotropic hypogonadism 54. Iwamoto H, Yoshida A, Suzuki H, et al. A man with treated with recombinant human follicle-stimulating hypogonadotropichypogonadism successfully treated hormone and human chorionic gonadotropin. Fertil with nasal administration of the low-dose gonado­ Steril. 2009;92(2):594-604. tropin-relasing hormone analog buserelin. Fertil Steril. 40. Pitteloud N, Durrani S, Raivio T. Complex genetics 2009;92(3):1169.e1-3. in idiopathic hypogonadotropic hypogonadism. In: 55. Lindner J, McNeil LW, Marney S, et al. Characterization Quinton R (Ed). Front Horm Res. 2010;39:142-53. of human anti-luteinizing hormone-releasing hormone 41. MacColl GS, Quinton R, Bülow HE. Biology of KAL 1 (LRH) antibodies in the serum of a patient with isolated and its orthologs: implication for X-linked Kallmann gonadotropin deficiency treated with synthetic LRH. syndrome and the search for novel candidate genes. In: J Clin Endocrinol Metab. 1981;52(2):267-70. Quinton R (Eds): Kallmann Syndrome and hypogonad­ 56. Depenbusch M, von Eckardstein S, Simoni M, et al. otropichypogonadism. Front Horm Res. 2010;39:62-77. Maintenance of spermatogenesis in hy­p­­o­­gona­d­ot­ro­ 42. Al-Ansari AA, Khalil TH, Kelani Y, et al.Isolated p­­­­­­ichypogonadal men with human chorionic gonado­ follicle-stimulating hormone deficiency in men: tropin alone. Eur J Endocrinol. 2002;147:617-24. successful long-term gonadotropin therapy. Fertil Steril. 57. Burgués S, Calderón MD. Subcutaneous self-adminis­ 1984;42(4):618-26. tration of highly purified follicle stimulating hormone 43. Krassas GE, Pontikides N, Deligianni V, et al. A prospec­ and human chorionic gonadotrophin for the treatment tive controlled study of the impact of hypert hyroidism of male hypogonadotrophic hypogonadism. Spanish on reproductive function in males. J Clin Endocrinol Collaborative Group on Male Hypogonadotropic Metab. 2002;87(8):3667-71. Hypogonadism. Hum Reprod. 1997;12(5):980-6. 44. Zähringer S, Tomova A, von Werder K, et al. The 58. Kung AW, Zhong YY, Lam KS, et al. Induction of sper­ influence of hyperthyroidism on the hypothalamic- matogenesis with gonadotrophins in Chinese men pituitary-gonadal axis. Exp Clin Endocrinol Diabetes. with hypogonadotrophic hypogonadism. Int J Androl. 2000;108:282-9. 1994;17(5):241-7. 45. Velázquez EM, BellabarbaArata G. Effects of thyroid 59. Nieschlag E, Behre HM. Testosterone therapy. In: status on pituitary gonadotropin and testicular reserve Nieschlag E, Behre HM, Nieschlag S (Eds). Andrology, in men. Arch Androl. 1997;38(1):85-92. 3rd edition. Heidelberg: Springer; 2009. pp. 437-56. 46. Kasturi SS, Tannir J, Brannigan RE. The metabolic 60. Dohle GR, van Roijen JH, Pierik FH, et al. Subtotal syndrome and male infertility. J Androl. 2008;29:251-9. obstruction of the male reproductive tract. Urol Res. 47. Robeva R, Kirilov G, Tomova A, et al. Low testo­ 2003;31(1):22-4. sterone levels and unimpaired melatonin secretion in 61. Matorras R, Pérez C, Corcóstegui B, et al. Treatment of young males with metabolic syndrome. Andrologia. the male with follicle-stimulating hormone in intrau­ 2006;38:216-20. terine insemination with husband’s spermatozoa: a 48. Paradisi R, Busacchi P, Seracchioli R, et al. Effects of randomized study. Hum Reprod. 1997;12(1):24-8. high doses of recombinant human follicle-stimulating 62. Kamischke A, Behre HM, Bergmann M, et al. hormone in the treatment of male factor infertility: Recombinant human follicle-stimulating hormone for results of a pilot study. Fertil Steril. 2006;86(3):728-31. treatment of male idiopathic infertility: a randomized, 49. Büchter D, Behre HM, Kliesch S, et al. Pulsatile GnRH double-blind, placebo-controlled, clinical trial. Hum or human chorionic gonadotropin/human menopausal Reprod. 1998;13(3):596-03. gonadotropin as effective treatment for men with hypo­ 63. Foresta C, Bettella A, Merico M, et al. Use of recombinant gonadotropic hypogonadism: a review of 42 cases. Eur J human follicle-stimulating hormone in the treatment of Endocrinol. 1998;139(3):298-303. male factor infertility. Fertil Steril. 2002;77(2):238-44. 50. Liu L, Banks SM, Barnes KM, et al. Two-year 64. Ashkenazi J, Bar-Hava I, Farhi J, et al. The role of puri­ comparison of testicular responses to pulsatile fied follicle stimulating hormone therapy in the male gonadotropin-releasing hormone and exogenous partner before intracytoplasmic sperm injection. Fertil gonadotropins from the inception of therapy in men Steril. 1999;72(4):670-3. 77 Section 2 Male Factor Infertility

65. Liu PY, Handelsman DJ. The present and future state 80. Radicioni A, Paris E, Dondero F, et al. Recombinant- of hormonal treatment for male infertility. Hum Reprod growth hormone (rec-hGH) therapy in infertile men Update. 2003;9(1):9-23. with idiopathic oligozoospermia. Acta Eur Fertil. 66. Kamischke A, Nieschlag E. Analysis of medical 1994;25(5):311-7. treatment of male infertility. Hum Reprod. 1999;14 81. Shoham Z, Conway GS, Ostergaard H, et al. Cotreatment (Suppl 1):1-23. with growth hormone for induction of spermatogenesis 67. Vandekerckhove P, Lilford R, Vail A, et al. Clomiphene in patients with hypogonadotropic hypogonadism. or tamoxifen for idiopathic oligo/as the nospermia. Fertil Steril. 1992;57(5):1044-51. Cochrane Database Syst Rev. 2000;(2):CD000151. 82. Byrne MM, Rolf C, Depenbusch M, et al. Lack of 68. Kadioglu TC, Köksal IT, Tung M, et al. Treatment of effect of a single i.v. dose of oxytocin on sperm output idiopathic and post varicocelectomy oligozoospermia in severely oligozoospermic men. Hum Reprod. with oral tamoxifen citrate. BJU Int. 1999;83(6):646-8. 2003;18(10):2098-02. 69. Shabsigh A, Kang Y, Shabsign R, et al. Clomiphene 83. Klibanski A. Clinical practice. Prolactinomas. N Engl citrate effects on testosterone/estrogen ratio in male J Med. 2010;362(13):1219-26. hypogonadism. J Sex Med. 2005;2(5):716-21. 84. Ries LAG, Eisner MP, Kosary CL, et al. SEER Cancer Statistics [Online] Available from www.seer.cancer. 70. Hill S, Arutchelvam V, Quinton R. Enclomiphene, an gov/csr/1975_2000/. [Accessed July 30, 2007]. estrogen receptor antagonist for the treatment of testos­ 85. Shetty G, Meistrich ML. Hormonal approaches to terone deficiency in men. I Drugs. 2009;12:109-19. pre­servation and restoration of male fertility after cancer 71. Whitten SJ, Nangia AK, Kolettis PN. Select patients treatment. J Natl Cancer Inst Monogr. 2005;(34):36-9. with hypogonadotropic hypogonadism may respond 86. Meistrich ML, Wilson G, Huhtaniemi I. Hormonal treat­ to treatment with clomiphene citrate. Fertil Steril. ment after cytotoxic therapy stimulates recovery of sper­ 2006;86:1664-68. matogenesis. Cancer Res. 1999;59(15):3557-60. 72. Kaminetsky J, Hemani ML. Clomiphene citrate and enclo­ 87. Shuttlesworth GA, de Rooij DG, Huhtaniemi I, et miphene for the treatment of hypogonadal androgen al. Enhancement of a spermatogonial proliferation deficiency. Expert OpinInvestig Drugs. 2009;18(12): and differentiation in irradiated rats by gonado­ 1947-55. tropin-releasing hormone antagonist administration. 73. Adamopoulos DA, Pappa A, Billa E, et al. Effectiveness Endocrinology. 2000;141(1):37-49. of combined tamoxifen citrate and testosterone unde­ 88. Meistrich ML, Kangasniemi M. Hormone treatment canoate treatment in men with idiopathic oligozoo­ after irradiation stimulates recovery of ratspermato­ spermia. Fertil Steril. 2003;80(4):914-20. genesis from surviving spermatogonia. J Androl. 74. Maier U, Hienert G. Tamoxifen and kallikrein in therapy 1997;18(1):80-7. of oligoasthenozoospermia: results of a randomized 89. Masala A, Faedda R, Alagna S, et al. Use of testoster­ study. Eur Urol. 1990;17(3):223-5. oneto prevent cyclophosphamide-inducedazoospermia. 75. Patry G, Jarvi K, Grober ED, et al. Use of the aromatase Ann Intern Med. 1997;126(4):292-5. inhibitor letrozole to treat male infertility. Fertil Steril. 90. Ogawa T, Dobrinski I, Avarbock MR, et al. Leuprolide, 2009;92(2):829.e1-2 a gonadotropin-releasing hormone agonist, enhances 76. Ramasamy R, Ricci JA, Palermo GD, et al. Successful colonization after spermatogonial transplantation into fertility treatment for Klinefelter’s syndrome. J Urol. mouse testes. Tissue Cell. 1998;30(5):583-8. 2009;182:1108-13 91. Dobrinski I, Ogawa T, Avarbock MR, et al. Effect of the 77. Clark R, Sherins RJ. Treatment of men with idio­ GnRH-agonist leuprolide on colonization of recipient­ pathic oligozoospermic infertility using the aromatase testes by donor spermatogonial stem cells after trans­ inhibitor testolactone. Results of a double-blinded, plantation in mice. Tissue Cell. 2001;33(2):200-7. randomized, placebo-controlled trial with crossover. 92. Wildt L, Haulser A, Marshall G, et al. Frequency and J Androl. 1989;10(3):240-7. amplitude of gonadotropin-releasing hormone stimula­ 78. Hull KL, Harvey S. Growth hormone: roles in male tion and gonadotropin secretion in the rhesus monkey. reproduction. Endocrine. 2000;13(3):243-50. Endocrinology. 1981;109:376-85. 79. Lee KO, Ng SC, Lee PS, et al. Effect of growth hormone 93. Carruthers M. Androgen deficiency in the adult male: therapy in men with severe idiopathic oligozoospermia. causes, diagnosis and treatment. London: Taylor & Eur J Endocrinol. 1995;132(2):159-62. Francis; 2004.

78