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Home , Oxytocin

Animal Science 434 Reproductive

Lecture 6 and 7: What is the function of the Endocrinology ?

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 • can be used to regulate body functions • A ductless gland » growth (anabolic steroids) • Secretes substances (hormones) into » (GH or STH) blood or lymph that affect cells elsewhere » control (, ) in the body » (PGF α) 2 • The does not involve loss of » superovulation and embryo transplant (FSH,eCG) » parturition () Exocrine Gland

• 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 Adrenal B. Type of action Pineal Uterus Pituitary 1. Primary hormone of 2. Metabolic hormone C. Chemical Structure Testes (in bull) 1. General structure – and polypeptides – Steroids – Fatty acids – Modified 2. Size

Classification and Properties of Hormone Location of the Hypothalamus and 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 • releasing hormone (GnRH) • short chain polypeptides (3 - 44 amino acids) » LH, FSH release • Thyrotrophin releasing hormone (TRH) TSH and release B. General Function » • to cause the release of trophic hormones from the • Corticotrophin releasing hormone (CRH) gland » ACTH release • releasing hormone (GH-RH) • (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. Anterior Pituitary Gland » Follicle stimulating hormone (FSH) » (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 • 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 • Oxytocin - contraction of smooth muscle • Human Chorionic Gonadotropin (HCG) » Maintains CL and pregnancy • Placental Lactogen (PL) » Development of the in the mother • Steroids - and Progesterone

Gonadal Polypeptide Hormones Gonadal Steroids • » 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 for transport C. Type of Steroids » Androgens - » Estrogen - Estradiol » Progestin - Progesterone

Phospholipids Other Hormones • 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. 1. Secreted from the . 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 • 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 B. Type of action a. Perganol - superovulation 1. Primary hormone of reproduction (FSH, LH, estradiol, progesterone) 2. Metabolic hormone (thyroxin, , 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 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

ANDROSTEINDIONE ESTRONE

TESTOSTERONE ESTRADIOL These hormones can be given orally!