Animal Science 434 Reproductive Physiology" Lecture 6 and 7: What is the function of the Endocrinology endocrine system?" Integration of Body Functions" • nervous and endocrine systems are similar • nervous system » seconds Neuro-endocrine Response " • endocrine system » minutes and hours Manipulation of the Endocrine System" Endocrine Gland" • Hormones can be used to regulate body functions • A ductless gland" » growth (anabolic steroids) • Secretes substances (hormones) into » lactation (GH or STH) blood or lymph that affect cells elsewhere » birth control (Estradiol, Progesterone) in the body" » estrous cycle (PGF α) 2 • The secretion does not involve loss of » superovulation and embryo transplant (FSH,eCG) tissue" » parturition (oxytocin) Exocrine Gland" Hormone" • A gland with ducts that are used for • Substance produced by endocrine gland secretion • Acts on cells, tissues or organs at a place other than where produced • Acts as a catalyst. Classification and Properties of Hormone" Endocrine Glands" A. Site of Production Hypothalamus" Adrenal" Ovary" B. Type of action Pineal" Uterus" Pituitary" 1. Primary hormone of reproduction 2. Metabolic hormone Placenta" C. Chemical Structure Testes" (in bull)" 1. General structure – Proteins and polypeptides – Steroids Thyroid" – Fatty acids – Modified amino acid 2. Size Pancreas" Classification and Properties of Hormone" Location of the Hypothalamus and Pituitary Gland" A. Site of Production B. Type of action 1. Primary hormone of reproduction 2. Metabolic hormone C. Chemical Structure 1. General structure – Proteins and polypeptides – Steroids – Fatty acids – Modified amino acid 2. Size Hypothalamus" Function of Hypothalamus" • appetite • thirst • body temperature • vasomotor activity • emotion • use of body nutrient reserves • activity of intestine • sleep • sexual behavior • Production and release of releasing hormones Releasing Hormones of the Hypothalamus" Releasing Hormones of the Hypothalamus" C.Hormones A. Structure • Gonadotropin releasing hormone (GnRH) • short chain polypeptides (3 - 44 amino acids) » LH, FSH release • Thyrotrophin releasing hormone (TRH) TSH and prolactin release B. General Function » • to cause the release of trophic hormones from the • Corticotrophin releasing hormone (CRH) anterior pituitary gland » ACTH release • Growth hormone releasing hormone (GH-RH) • Somatostatin (growth hormone inhibiting hormone) Hypothalamus" Hypothalamus" Preoptic nuclei cell" Nerve Cells" Superior hypophyseal artery" Capillary plexus" Hypophyseal Cells of the Anterior portal vessels" Pituitary" • LH" Posterior • FSH" pituitary" • Prolactin" • STH" • TSH" Capillary • ACTH" plexus" Anterior Pituitary Hormones" A. Structure 1. glycoproteins or proteins B. Hormones Hypothalamus and ! 1. gonadotropins Anterior Pituitary Gland" » Follicle stimulating hormone (FSH) » Luteinizing hormone (LH) » Prolactin Anterior Pituitary Hormones" Structure of LH, FSH and TSH" 2.Other trophic hormones • Made of 2 amino acid chains • Adrenal Corticotropin (ACTH) • thyroid stimulating hormone (TSH) α • growth hormone (GH or STH) S S β • α chains are the same • β chains differ and give specificity Hypothalamus" Supraoptic Hypothalamus" nuclei cell" Paraventricular Nerve nuclei cell" Cells" Capillary plexus" Posterior Nuclei that produce Anterior Pituitary" pituitary" posterior pituitary • Oxytocin" hormones" • ADH" Posterior Pituitary Hormones" Placental Hormones" A.Structure • polypeptides (9 amino acids) • Equine Chorionic Gonadotropin (eCG) B. Hormone » Formation of accessory CL and maintains pregnancy • Oxytocin - contraction of smooth muscle • Human Chorionic Gonadotropin (HCG) » Maintains primate CL and pregnancy • Placental Lactogen (PL) » Development of the mammary gland in the mother • Steroids - Estrogen and Progesterone Gonadal Polypeptide Hormones" Gonadal Steroids" • Relaxin » Secreted by CL during pregnancy. A. General » Parturition » Origin - ovary, testis, adrenal » Structure • Inhibin » Inhibits FSH release Side Chain Cleavage" Gonadal Steroids Cont." A.# General Cont. » Solubility – Bound to a binding protein for transport C.# Type of Steroids » Androgens - Testosterone » Estrogen - Estradiol » Progestin - Progesterone Phospholipids" Other Hormones" Prostaglandins" • Many tissues" PLA2" A. Prostaglandins • Local effects" COOH" • Degraded in lung" Arachidonic Acid" 1.#PGF2α 2.#PGE2α Cyclo-oxygenase" Inhibited by o" COOH" PGG2" o" aspirin! OOH" COOH" PGH " o" 2 o" OH" PGE2" PGF2" O" OH" COOH" COOH" OH" OH" OH" OH" Phospholipids" Other Hormones" PLA2" COOH" Arachidonic Acid" B. Melatonin 1. Secreted from the pineal gland. Cyclo-oxygenase" 2. Is a modified amino acid COOH" o" 3. Functions to integrate effects of light on PGG2" o" OOH" reproductive processes. • Vasodilation" • Vasoconstriction" • Maintain CL" • CL regression" COOH" o" • Ovulation" • Ovulation" PGH2" • Implantation" o" • Parturition" OH" • Sperm transport" PGE2" PGF2" O" OH" COOH" COOH" OH" OH" OH" OH" Other Hormones" Classification and Properties of Hormone" C. Human Menopausal Gonadotropin (hMG) A. Site of Production 1.# Anterior pituitary gland » Secreted in menopause, FSH-like activity » Isolated from urine B. Type of action a.#Perganol - superovulation 1. Primary hormone of reproduction (FSH, LH, estradiol, progesterone) 2. Metabolic hormone (thyroxin, insulin, STH) Chemical Structure of Hormones" Classification and Properties of Hormone" polypeptide "modified amino acid "protein "sex steroid "fatty acid" GnRh "melatonin "LH "Estradiol "PGF" 2α • Chemical Structure TRH " "FSH "Progesterone" » Polypeptides - hypothalamic CRH " "Prolactin "Testosterone" » Protein - pituitary, gonad GHRH " "ACTH" » Steroids - gonad, adrenal Somatistatin " "TSH" Oxytocin " "GH or STH" » Fatty acid - many sources, prostaglandins " "Relaxin" » Modified amino acid - pineal " "Inhibin" " " "" Chemical Structure of Hormones" Chemical Structure of Hormones Cont." Molecular size of hormones that regulate reproduction" Hormone "Molecular Weight" Polypeptide and protein hormones FSH 30,000 to 37,000 LH 26,000 to 32,000 are made of peptide bonds Prolactin 23,000 to 25,000 HCG 37,700 NH3 eCG 28,000 R CH Inhibin >10,000 C O Relaxin 6,500 HN Peptide ACTH 4,500 HC R Bond Oxytocin 1,007 O C GnRH 1,200 NH Estradiol 300 R CH Testosterone 300 COO- Progesterone 300 PGF 300 These hormones can not be given orally!" 2α Chemical Structure of Hormones Cont." Mechanism of Hormone Action" CHOLESTEROL Steroids PREGNENOLONE ADRENAL OVARY OR TESTES PROGESTERONECORTISOL " PROGESTERONE 17α OH-PROGESTERONE CORTISOL" ANDROSTEINDIONE ESTRONE TESTOSTERONE ESTRADIOL These hormones can be given orally!".