DOCSLIB.ORG

Hormonal Mechanisms in the Onset of Puberty RONALD S

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Hormonal Mechanisms in the Onset of Puberty RONALD S Postgrad Med J: first published as 10.1136/pgmj.51.594.200 on 1 April 1975. Downloaded from Postgraduate Medical Journal (April 1975) 51, 200-208. Hormonal mechanisms in the onset of puberty RONALD S. SWERDLOFF* WILLIAM D. ODELL M.D. M.D., Ph.D. Division of Endocrinology, Harbor General Hospital Campus, U.C.L.A. School of Medicine, U.S.A. Summary Sexual maturation is associated with increasing levels I I II >Apex of sex steroids. These steroidal events are the result of strength spurt complex changes that occur at several functional levels including the hypothalamus, pituitary, gonad and Height spurt I adrenal gland. These changes, as outlined in Table 3, 10-5 - 16 13 5 - 17 5 are often interrelated. Penis While considerable progress has been made in our 10 5-14-5 12'-5-16-5 understanding of the hormonal events associated with Testis sexual maturation, many important questions remain 9 5 - 13 5 13-5- 17 unanswered. Further intensive investigation will be Gonadal rating 2'3 M4 5 required before we have a lucid understanding of the physiological basis of the sequence of hormonal events Pubic hair 21llI1IIIIlII3IIIIIII4lIlIIIIlII5llIlIIiIiIii by copyright. which occur during the pubertal process. 8 9 10 11 12 13 14 15 16 17 Age (years) Sexual maturation FIG. 2. Sequence of development of physical changes The transformation of a sexually immature child associated with puberty in boys. The numbers 2-5 refer into an adult capable of normal reproductive com- to the Tanner stages of pubic hair and genital develop- petence is the result of a complex series of hormonal ment (with permission from Marshall and Tanner, 1970). events. The sequence of development of the many physical changes associated with puberty have been carefully documented by Marshall and Tanner (1969, 1970). The physical changes which occur over a time http://pmj.bmj.com/ span of several years have been subdivided into several stages for simpler discussion of chronology, relationship to hormonal changes and diagnosis of abnormal maturational development. The widely Height spurt I U used classification system of Marshall and Tanner 9 5 - 14 5 (1969, 1970) actually represents two classifications based on separate but Menarche U interrelated events, e.g. pubic on September 30, 2021 by guest. Protected 10-16 5 hair and genital development in the male. Figures 1 and 2 represent the chronology of these stages in Breast 2Q &3 #4 5 boys and girls during the past two decades in England. 8-13 13-18 Efforts have been made by several groups to develop Pubic hair 211111111311111114 11111111111115 a composite staging system to allow for easier correlation with hormonal events (e.g. Winter and e 9 10 11 12 13 14 15 16 17 Faiman, 1972a). Similar classification systems used in our 1 Age (years) clinics are presented in Table and 2. The ages of children in whom these pubertal stages are FIG. 1. Sequence of development of physical changes observed differ depending on the geographical and associated with puberty in girls. The numbers 2-5 refer to the Tanner stages of pubic hair and breast develop- nutritional environment of the children. The latter ment (with permission from Marshall and Tanner, 1970). factor has been proposed as the explanation for the trend toward the earlier development of menarche * Recipient of USPHS Career Development Award #5 (Tanner, 1962; Frisch, 1972) observed over the past K04 HD 70436-02. century. Postgrad Med J: first published as 10.1136/pgmj.51.594.200 on 1 April 1975. Downloaded from Hormonal mechanisms in the onset ofpuberty 201 TABLE 1. Composite stages of sexual development in possibly prolactin). Secretion of LH and FSH males depends on the stimulatory effects of the hypo- thalamic releasing hormone, GnRH (Schally, Kastin Stage Description and Arimura, 1971). GnRH secretion is regulated by P-1 Preadolescent; largest testes diameter < 2-4 hypothalamic monoamines such as norepinephrine, cm; no pubic hair or penile enlargement dopamine and serotonin (Kamberi, Mical and P-2 Sparse pubic hair, mainly at base of penis; Porter, 1971). Higher CNS structures undoubtedly testis diameter 2-43-2 cm; scrotal skin reddened; little penile enlargement influence the production of the latter substances. P-3 Pubic hair darker, coarser, but limited in dis- Both hypothalamic and pituitary function are tribution; early penis enlargement; sparse influenced by the gonads. In the male, testosterone, axillary hair; testes diameter 3-3-40 cm; dihydrotestosterone, oestradiol and perhaps other scrotal skin darker gonadal substances act via negative feedback to P-4 Adult pubic hair; moderate axillary hair; inhibit the secretion of LH and FSH (Swerdloff et al., testis diameter 4 14-5 cm 1973; Walsh, Swerdloff and Odell, 1973a, b). It is P-5 Adult secondary characteristics; testis dia- meter than 4-5 cm likely that this negative feedback occurs both at the greater hypothalamic level (inhibiting the secretion of Adapted from Marshall and Tanner (1970) and Winter GnRH) (Smith and Davidson, 1967) and at the and Faiman (1972a). pituitary level (Wollessen et al., 1974; Vera, Swerd- loff and Odell, 1974) inhibiting the effects of GnRH TABLE 2. Composite stages of sexual development in on LH and FSH secretion. Thus, in a normal adult females male, castration results in increased secretion of LH Stage Description and FSH owing to the absence of the inhibitory effects of gonadal steroids. Treatment of such a P-1 Preadolescent person with androgens and/or oestrogens results in a P-2 Breast budding; early labial hair growth return of these gonadotrophins towards normal. The by copyright. P-3 Increased breast size with palpable glandular for the male is in 3. tissue; no separating of breast contours; feedback system depicted Fig. moderately dark coarser labial hair over mons pubis Extrohypothalamic Environment P-4 Further enlargement of breasts with projec- CNS tion of areola above breast plane; lateral spread of pubic hair P-5 Adult breast size and pubic hair distribution + Cyclic | Tonic area area Adapted from Marshall and Tanner (1969). + Catecholomines http://pmj.bmj.com/ events in puberty GNRH - Metabolic Hormonal effects With the exception of gonadal size, most of the visible changes associated with puberty in both sexes Pituitary are due to increased production of steroid hormones. FSH LH These hormones are secreted directly by the gonads and adrenals or are converted from precursor steroids Testis secreted by the adrenals. In the male, pubic, axillary on September 30, 2021 by guest. Protected and facial hair, phallic enlargement, change in . muscle mass and epiphyseal closure all result from sExtrogonodal sourcesT+DHT;E2+ X Degrsdative increasing concentrations of androgens. These ~~~~~~systems androgens are predominantly produced by the FIG. 3. Hypothalamic-pituitary-gonadal feedback system but a small contribution is due to the direct of the male. The extragonadal sources of androgen re- testes, ferred to include androgens and androgen precursors secretion of weak androgens and androgen pre- produced by the adrenal glands. The testis directly cursors from the adrenal glands. In the female, secretes testosterone, dehydrotestosterone and oestradiol. breast development, female fat distribution, vaginal Other substances have been postulated to be secreted by and uterine development, linear growth velocity and the testes which are believed to have an influence on FSH secretion. Such a substance referred to as )X' in the skeletal maturation are the result of increasing diagram has been given various names including oestrogen secretion by the ovary. The mechanism by 'inhibin'. which increased production of adrenal androgens (adrenarche) occurs at puberty is incompletely In the female (as in the male), a tonic negative understood. The gonads are under the control of the feedback system exists and ovarian steroids (oestro- pituitary gonadotrophic hormones (LH, ESH and gen and progesterone) inhibit LH and FSH secretion Postgrad Med J: first published as 10.1136/pgmj.51.594.200 on 1 April 1975. Downloaded from 202 R. S. Swerdloffand W. D. Odell (Odell and Swerdloff, 1968; Swerdloff and Odell, Folliculor Luteol - 1969). This inhibitory influence probably occurs at phIphasee pphasee I both hypothalamic and pituitary levels. In addition, the female has a positive feedback system (Fig. 4) by which oestrogens stimulate LH secretion (Swerd- loff and Odell, 1969; Yenn, 1971). Progestogens may synergize with oestrogens in this stimulatory action on LH secretion and they may be necessary for E stimulation at midcycle (Odell and Swerdloff, 1968; Swerdloff, Jacobs and Odell, 1972a). This stimulatory action ofgonadal steroids results in the pre-ovulatory surge of LH and FSH observed at midcycle. 300 - E 200 100 -E2 60 Degradative , systems - Metabolic effects by copyright. E 40r E 15 - LH j1 FIG. 4. Hypothalamic-pituitary-gonadal feedback system of the female. 10 , serum Figure 5 depicts the cyclic changes of LH, http://pmj.bmj.com/ FSH, oestradiol and progesterone during a normal E menstrual cycle (Abraham et al., 1971). The follow- F1 ing sequence of events occurs. FSH rises early in the 51 cycle and stimulates growth of the ovarian follicle. The growing follicle secretes increasing amounts of 4 10 14 20 28 oestradiol (and 17-a-hydroxy-progesterone). When Davs a critical the oestradiol concentration reaches level, FIG. 5. Daily serum LH, FSH, oestradiol-17B and pro- it triggers release of large quantities of LH and FSH. gesterone concentrations in a normal menstrual cycle on September 30, 2021 by guest. Protected Ovulation then occurs and a corpus luteum develops. (with permission from Abraham et al., 1971). Progesterone concentrations, which begin to rise just before the midcycle LH peak, are markedly increased Gonadotrophins during the luteal phase. The elevated concentrations Until recently, most physicians believed that the of oestradiol and progesterone act via the negative prepubertal child was not able to secrete gonado- feedback system to inhibit secretion of LH and FSH.
Load more

Recommended publications
  • Sample Chapter
    LCMS_Chap09 (JB-D) 8/5/06 3:14 pm Page 193 9 LC-MS in doping control Detlef Thieme Introduction adjacent fields with similar analytical prospects, like veterinary residue control (predominantly dealing with identification of growth promoters Definition of doping in various matrices), forensic sciences (the major- ity of doping-relevant substances are scheduled Doping analysis comprises a diversity of sub- as controlled substances in most countries), stance classes with different pharmaceutical and environmental analysis (e.g. steroids in waste chemical properties. Therefore, the discussion of water) or clinical chemistry (e.g. due to the the suitability of liquid chromatography-mass increasing relevance of steroid hormone replace- spectrometry (LC-MS) in doping analysis needs ment therapy). to distinguish various categories. This chapter describes the key fields of appli- According to its formal definition, a doping cation of LC-MS in routine doping control (i.e. violation in sports can be caused by various screening analysis, confirmation and quantifica- events, e.g.: tion of positive results) extra to particular • the detection of a prohibited substance or research activities. The latter are focused on the metabolites or markers of that substance (as intended technical improvements (e.g. extension defined by the recent document [1] of the of detection time windows, reduction of turn- World Anti-Doping Agency [WADA]) in the around times and costs) of conventional analyti- athlete’s specimen cal procedures and, in particular, on the detection • the use of prohibited substances or methods of prohibited substances that cannot be ade- • possession or trafficking prohibited substances quately identified so far (e.g.
    [Show full text]
  • From Adrenarche to Aging of Adrenal Zona Reticularis: Precocious Female Adrenopause Onset
    ID: 20-0416 9 12 E Nunes-Souza et al. Precocious female 9:12 1212–1220 adrenopause onset RESEARCH From adrenarche to aging of adrenal zona reticularis: precocious female adrenopause onset Emanuelle Nunes-Souza1,2,3, Mônica Evelise Silveira4, Monalisa Castilho Mendes1,2,3, Seigo Nagashima5,6, Caroline Busatta Vaz de Paula5,6, Guilherme Vieira Cavalcante da Silva5,6, Giovanna Silva Barbosa5,6, Julia Belgrowicz Martins1,2, Lúcia de Noronha5,6, Luana Lenzi7, José Renato Sales Barbosa1,3, Rayssa Danilow Fachin Donin3, Juliana Ferreira de Moura8, Gislaine Custódio2,4, Cleber Machado-Souza1,2,3, Enzo Lalli9 and Bonald Cavalcante de Figueiredo1,2,3,10 1Pelé Pequeno Príncipe Research Institute, Água Verde, Curitiba, Parana, Brazil 2Faculdades Pequeno Príncipe, Rebouças, Curitiba, Parana, Brazil 3Centro de Genética Molecular e Pesquisa do Câncer em Crianças (CEGEMPAC) at Universidade Federal do Paraná, Agostinho Leão Jr., Glória, Curitiba, Parana, Brazil 4Laboratório Central de Análises Clínicas, Hospital de Clínicas, Universidade Federal do Paraná, Centro, Curitiba, Paraná, Brazil 5Serviço de Anatomia Patológica, Hospital de Clínicas, Universidade Federal do Paraná, General Carneiro, Alto da Glória, Curitiba, Parana, Brazil 6Departamento de Medicina, PUC-PR, Prado Velho, Curitiba, Parana, Brazil 7Departamento de Análises Clínicas, Universidade Federal do Paraná, Curitiba, Paraná, Brazil 8Pós Graduação em Microbiologia, Parasitologia e Patologia, Departamento de Patologia Básica – UFPR, Curitiba, Brazil 9Institut de Pharmacologie Moléculaire et Cellulaire CNRS, Sophia Antipolis, Valbonne, France 100Departamento de Saúde Coletiva, Universidade Federal do Paraná, Curitiba, Paraná, Brazil Correspondence should be addressed to B C de Figueiredo: [email protected] Abstract Objective: Adaptive changes in DHEA and sulfated-DHEA (DHEAS) production from adrenal zona reticularis (ZR) have been observed in normal and pathological conditions.
    [Show full text]
  • The-Male-Brain.Pdf
    ALSO BY LOUANN BRIZENDINE, M.D. The Female Brain To the men in my life: My husband, Dr. Samuel Herbert Barondes My son, John “Whitney” Brizendine My brother, William “Buzz” Brizendine II And in memory of my father, Reverend William Leslie Brizendine CONTENTS Acknowledgments The Male Brain (diagram) The Cast of Neurohormone Characters Phases of a Male’s Life INTRODUCTION What Makes a Man ONE The Boy Brain TWO The Teen Boy Brain THREE The Mating Brain: Love and Lust FOUR The Brain Below the Belt FIVE The Daddy Brain SIX Manhood: The Emotional Lives of Men SEVEN The Mature Male Brain EPILOGUE The Future of the Male Brain APPENDIX The Male Brain and Sexual Orientation Notes References ACKNOWLEDGMENTS This book had its beginnings during my educational years at U.C. Berkeley, Yale, Harvard, and U.C. London, so I would like to thank those teachers who most influenced my thinking during those years: Frank Beach, Mina Bissell, Harold Bloom, Marion Diamond, Walter Freeman, Florence Haseltine, Richard Lowenstein, Daniel Mazia, Fred Naftolin, Stanley Jackson, Roy Porter, Carl Salzman, Leon Shapiro, Rick Shelton, Gunter Stent, Frank Thomas, George Valliant, Clyde Willson, Fred Wilt, Richard Wollheim. During my years on the faculty at Harvard and UCSF, my thinking has been influenced by: Cori Bargman, Samuel Barondes, Sue Carter, Regina Casper, Lee Cohen, Mary Dallman, Allison Doupe, Deborah Grady, Mel Grumbach, Leston Havens, Joel Kramer, Fernand Labrie, Sindy Mellon, Michael Merzenich, Joseph Morales, Kim Norman, Barbara Parry, Victor Reus, Eugene Roberts, Nirao Shah, Carla Shatz, Stephen Stahl, Marc Tessier-Lavigne, Rebecca Turner, Owen Wolkowitz, Chuck Yingling, and Ken Zack.
    [Show full text]
  • Premature Adrenarche: a Guide for Families
    Pediatric Endocrinology Fact Sheet Premature Adrenarche: A Guide for Families Premature adrenarche (PA) is one of the most common or ovarian) tumor, but in those cases, very rapid growth with diagnoses made in children referred to a specialist for signs enlargement of the clitoris in a girl or the penis in a boy will of early puberty. Its key features are: be a sign the child needs further testing. In addition, exposure 1) Appearance of pubic and/or underarm hair in girls to hormonal supplements may cause the appearance of PA. younger than 8 years or boys younger than 9 years 2) Adult-type underarm odor, often requiring use of Does PA cause any harm to the child? deodorants There are generally no health problems caused by PA. Girls 3) Absence of breast development in girls or of genital en- with PA may have periods a bit earlier than the average, but largement in boys (which, if present, often point to the usually not before age 10. diagnosis of true precocious puberty) It is known that girls with PA are at increased risk of de- 4) Many children are greater than average in height, and veloping a disorder called polycystic ovary syndrome (PCOS) often are above the 90th percentile in their teenage years. The signs of PCOS include irregular or absent periods and sometimes increased facial hair. Because Hormonal basis most girls with PCOS are overweight, maintaining a healthy PA is caused by an earlier-than-normal increase in pro- weight with a healthy diet and plenty of exercise is the best duction of weak male-type hormones (mainly one called way to lower the risk that your child will develop PCOS.
    [Show full text]
  • Review Article Physiologic Course of Female Reproductive Function: a Molecular Look Into the Prologue of Life
    Hindawi Publishing Corporation Journal of Pregnancy Volume 2015, Article ID 715735, 21 pages http://dx.doi.org/10.1155/2015/715735 Review Article Physiologic Course of Female Reproductive Function: A Molecular Look into the Prologue of Life Joselyn Rojas, Mervin Chávez-Castillo, Luis Carlos Olivar, María Calvo, José Mejías, Milagros Rojas, Jessenia Morillo, and Valmore Bermúdez Endocrine-Metabolic Research Center, “Dr. Felix´ Gomez”,´ Faculty of Medicine, University of Zulia, Maracaibo 4004, Zulia, Venezuela Correspondence should be addressed to Joselyn Rojas; [email protected] Received 6 September 2015; Accepted 29 October 2015 Academic Editor: Sam Mesiano Copyright © 2015 Joselyn Rojas et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The genetic, endocrine, and metabolic mechanisms underlying female reproduction are numerous and sophisticated, displaying complex functional evolution throughout a woman’s lifetime. This vital course may be systematized in three subsequent stages: prenatal development of ovaries and germ cells up until in utero arrest of follicular growth and the ensuing interim suspension of gonadal function; onset of reproductive maturity through puberty, with reinitiation of both gonadal and adrenal activity; and adult functionality of the ovarian cycle which permits ovulation, a key event in female fertility, and dictates concurrent modifications in the endometrium and other ovarian hormone-sensitive tissues. Indeed, the ultimate goal of this physiologic progression is to achieve ovulation and offer an adequate environment for the installation of gestation, the consummation of female fertility. Strict regulation of these processes is important, as disruptions at any point in this evolution may equate a myriad of endocrine- metabolic disturbances for women and adverse consequences on offspring both during pregnancy and postpartum.
    [Show full text]
  • Reproductive Physiology and Endocrinology
    Comparative Veterinary Reproduction and Obstetrics, Instructor: Patrick J. Hemming DVM LECTURE 3 Reproductive Physiology and Endocrinology A. Reproductive endocrinology 1. Reproductive organs and hormones of the endocrine system; Endocrine control of estrus cycles, pregnancy, spermatogenesis, sexual development and behavior and all other aspects of reproduction is the responsibility of the hypothalamic-pituitary-gonadal axis. Hypothalamic hormones control the release of pituitary hormones while pituitary hormones exert their effects on the development, function and hormone synthesis of the gonads. Gonadal hormones, in addition to direct effects on the genital organs, complete the hypothalamic-pituitary-gonadal axis by either suppressing or stimulating the production and/or release of hypothalamic and pituitary hormones in what is called negative feedback or positive feedback mechanisms. Gonadal Hormones also exert influence over growth, behavior, organs or tissue function such as in the mammary glands. Most other endocrine systems have similar feedback mechanisms. A) Hypothalamus; the master endocrine gland; The hypothalamus represents the interface of the central nervous system with the endocrine system. The hypothalamus receives direct CNS innervation from several areas of the brain stem and cerebrum. Direct and indirect visual, olfactory, auditory and touch sensory inputs also innervate areas of the hypothalamus. Neurons of the hypothalamus involved with reproduction also contain receptors for estrogen and other steroidal hormones, constituting the feedback mechanism. These neuronal and hormonal signals regulate the endocrine functions of the hypothalamus. Anatomically the hypothalamus is a diffuse area of the brain, composed of groups of neurons organized into distinct nuclei. These nuclei lie dorsal and rostral of the pituitary gland and stalk, in an area surrounding the third ventricle, in the most rostral portions of the brain stem.
    [Show full text]
  • Precocious Puberty Dominique Long, MD Johns Hopkins University School of Medicine, Baltimore, MD
    Briefin Precocious Puberty Dominique Long, MD Johns Hopkins University School of Medicine, Baltimore, MD. AUTHOR DISCLOSURE Dr Long has disclosed Precocious puberty (PP) has traditionally been defined as pubertal changes fi no nancial relationships relevant to this occurring before age 8 years in girls and 9 years in boys. A secular trend toward article. This commentary does not contain fi a discussion of an unapproved/investigative earlier puberty has now been con rmed by recent studies in both the United use of a commercial product/device. States and Europe. Factors associated with earlier puberty include obesity, endocrine-disrupting chemicals (EDC), and intrauterine growth restriction. In 1997, a study by Herman-Giddens et al found that breast development was present in 15% of African American girls and 5% of white girls at age 7 years, which led to new guidelines published by the Lawson Wilkins Pediatric Endocrine Society (LWPES) proposing that breast development or pubic hair before age 7 years in white girls and age 6 years in African-American girls should be evaluated. More recently, Biro et al reported the onset of breast development at 8.8, 9.3, 9.7, and 9.7 years for African American, Hispanic, white non-Hispanic, and Asian study participants, respectively. The timing of menarche has not been shown to be advancing as quickly as other pubertal changes, with the average age between 12 and 12.5 years, similar to that reported in the 1970s. In boys, the Pediatric Research in Office Settings Network study recently found the mean age for onset of testicular enlargement, usually the first sign of gonadarche, is 10.14, 9.14, and 10.04 years in non-Hispanic white, African American, and Hispanic boys, respectively.
    [Show full text]
  • Diagnosis and Management of Primary Amenorrhea and Female Delayed Puberty
    6 184 S Seppä and others Primary amenorrhea 184:6 R225–R242 Review MANAGEMENT OF ENDOCRINE DISEASE Diagnosis and management of primary amenorrhea and female delayed puberty Satu Seppä1,2 , Tanja Kuiri-Hänninen 1, Elina Holopainen3 and Raimo Voutilainen 1 Correspondence 1Departments of Pediatrics, Kuopio University Hospital and University of Eastern Finland, Kuopio, Finland, should be addressed 2Department of Pediatrics, Kymenlaakso Central Hospital, Kotka, Finland, and 3Department of Obstetrics and to R Voutilainen Gynecology, Helsinki University Hospital and University of Helsinki, Helsinki, Finland Email [email protected] Abstract Puberty is the period of transition from childhood to adulthood characterized by the attainment of adult height and body composition, accrual of bone strength and the acquisition of secondary sexual characteristics, psychosocial maturation and reproductive capacity. In girls, menarche is a late marker of puberty. Primary amenorrhea is defined as the absence of menarche in ≥ 15-year-old females with developed secondary sexual characteristics and normal growth or in ≥13-year-old females without signs of pubertal development. Furthermore, evaluation for primary amenorrhea should be considered in the absence of menarche 3 years after thelarche (start of breast development) or 5 years after thelarche, if that occurred before the age of 10 years. A variety of disorders in the hypothalamus– pituitary–ovarian axis can lead to primary amenorrhea with delayed, arrested or normal pubertal development. Etiologies can be categorized as hypothalamic or pituitary disorders causing hypogonadotropic hypogonadism, gonadal disorders causing hypergonadotropic hypogonadism, disorders of other endocrine glands, and congenital utero–vaginal anomalies. This article gives a comprehensive review of the etiologies, diagnostics and management of primary amenorrhea from the perspective of pediatric endocrinologists and gynecologists.
    [Show full text]
  • Who Unep 8 9 10 11 World Health Organization International Programme on Chemical Safety (Ipcs) Environmental Health Criteria Document On
    1 WORLD HEALTH ORGANIZATION IPCS 2 INTERNATIONAL LABOUR ORGANIZATION Unedited draft 3 UNITED NATIONS ENVIRONMENT PROGRAMME Restricted 4 5 6 7 WHO UNEP 8 9 10 11 WORLD HEALTH ORGANIZATION INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY (IPCS) ENVIRONMENTAL HEALTH CRITERIA DOCUMENT ON 12 PRINCIPLES FOR EVALUATING HEALTH RISKS IN CHILDREN 13 ASSOCIATED WITH EXPOSURE TO CHEMICALS 14 15 16 17 Draft Prepared by: Dr Germaine BUCK-LOUIS, Division of Epidemiology, Statistics and Preventive Research, NIH, National Institute of Child Health Development, USA; Dr Terri DAMSTRA, World Health Organization, International Programme on Chemical Safety, Interregional Research Unit, USA; Dr Fernando DIAZ-BARRIGA, Universidad Autonoma de San Luis Potosi, Facultad de Medicina, Mexico; Dr Elaine FAUSTMAN, Institute for Risk Analysis and Risk Communication, University of Washington, USA; Dr Ulla HASS, Danish Danish Institute of Food & Veterinary Research (FDIR), Department of Toxicology & Risk Assessment, Denmark; Dr Robert KAVLOCK, US Environmental Protection Agency, Reproduction Toxicology Facility, USA; Dr Carole KIMMEL, US Environmental Protection Agency, National Center for Environmental Assessment, USA; Dr Gary KIMMEL, Silver Spring, Maryland, USA; Dr Kannan KRISHNAN, University of Montreal, Canada; Dr Ulrike LUDERER, Center for Occupational and Environmental Health, University of California at Irvine, USA; Dr Linda SHELDON, US Environmental Protection Agency, Human Exposure and Atmospheric Sciences Division, USA. 1 1 2 TABLE OF CONTENTS 3 4 5 CHAPTER 1 – Executive
    [Show full text]
  • Premature Adrenarche
    Premature Adrenarche What is adrenarche? How will a healthcare provider evaluate Adrenarche is part of puberty. Specifically, it is the my child for premature adrenarche? development underarm and pubic hair, acne, oily skin • Your provider will ask when puberty changes were and hair, and body odor. It is caused by hormones first noticed, puberty timing in family members and called androgens which are made by the adrenal glands. if the child was potentially exposed to something Adrenarche usually happens around the time with hormones in it. of puberty when there is a growth spurt, breast • Physical exam, including checking for breast growth, and eventually periods start. This process development, signs of pubic hair growth, external usually occurs over 2 to 3 years. genitalia, and a skin exam. Adrenarche can start as early as age 8 and on average • Review of growth charts to look for the start of a begins to occur by age 10. However, adrenarche may growth spurt. occur slightly before or slightly after the other signs of puberty. • Bone age x-ray of the hand. • Lab tests including hormone levels may be ordered at the initial evaluation or at a follow-up visit. What is premature (early) adrenarche? Premature adrenarche is the growth of pubic or When would a healthcare provider want to underarm hair, body odor or acne before the age of 8. If do further evaluation? there are no other pubertal changes (specifically no breast growth, a growth spurt or menstrual bleeding), • If there are other signs of puberty prior to age 8 the pubic/underarm hair is considered a normal • Pubic hair is growing rapidly variation in development.
    [Show full text]
  • Characterization of Sterol Synthesis in Bacteria
    bioRxiv preprint doi: https://doi.org/10.1101/047233; this version posted April 5, 2016. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-ND 4.0 International license. 1 Characterization of sterol synthesis in bacteria 2 3 Jeremy H. Wei, Xinchi Yin and Paula V. Welander* 4 Department of Earth System Science, Stanford University, Stanford, CA, USA 5 6 7 *Correspondence: 8 Dr. Paula V. Welander 9 Stanford University 10 Department of Earth System Science 11 473 Via Ortega, Rm 140 12 Stanford, CA 94305 13 [email protected] 14 15 Running Title: Bacterial sterol synthesis 16 Keywords: lipid biosynthesis, sterols, biomarkers, squalene monooxygenase, oxidosqualene 17 cyclase, myxobacteria, methanotrophs, planctomycetes 18 1 bioRxiv preprint doi: https://doi.org/10.1101/047233; this version posted April 5, 2016. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-ND 4.0 International license. 19 Abstract 20 21 Sterols are essential components of eukaryotic cells whose biosynthesis and function in 22 eukaryotes has been studied extensively. Sterols are also recognized as the diagenetic precursors 23 of steranes preserved in sedimentary rocks where they can function as geological proxies for 24 eukaryotic organisms and/or aerobic metabolisms and environments. However, production of 25 these lipids is not restricted to the eukaryotic domain as a few bacterial species also synthesize 26 sterols.
    [Show full text]
  • Public Health Implications of Altered Puberty Timing
    SUPPLEMENT ARTICLE Public Health Implications of Altered Puberty Timing Mari S. Golub, PhDa,b, Gwen W. Collman, PhDc, Paul M. D. Foster, PhDd, Carole A. Kimmel, PhDe, Ewa Rajpert-De Meyts, MD, PhDf, Edward O. Reiter, MDg, Richard M. Sharpe, PhDh, Niels E. Skakkebaek, MD, DMScf, Jorma Toppari, MD, PhDi aDepartment of Environmental Toxicology, University of California, Davis, California; bCalifornia Environmental Protection Agency, Sacramento, California; cDivision of Extramural Research and Training, dNational Institute of Environmental Health Sciences, Research Triangle Park, North Carolina; eNational Center for Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, Washington, DC; fDepartment of Growth and Reproduction, Rigshospitalet, Copenhagen, Denmark; gDepartment of Pediatrics, Baystate Children’s Hospital, Springfield, Massachusetts; hMedical Research Council Human Reproductive Sciences Unit, University of Edinburgh, Edinburgh, Scotland; iDepartments of Physiology and Pediatrics, University of Turku, Turku, Finland The authors have indicated they have no financial relationships relevant to this article to disclose. ABSTRACT Changes in puberty timing have implications for the treatment of individual children, for the risk of later adult disease, and for chemical testing and risk assessment for the population. Children with early puberty are at a risk for accelerated skeletal matu- www.pediatrics.org/cgi/doi/10.1542/ ration and short adult height, early sexual debut, potential sexual abuse, and psy- peds.2007-1813G chosocial difficulties. Altered puberty timing is also of concern for the development doi:10.1542/peds.2007-1813G of reproductive tract cancers later in life. For example, an early age of menarche is a The views expressed in this article are those of the authors and do not necessarily risk factor for breast cancer.
    [Show full text]