Animal Science 434 Reproductive Physiology

Animal Science 434 Reproductive Physiology Endocrinology: Part B John Parrish Professor Department of Animal Sciences Mechanism of Hormone Action Mechanism of Hormone Action Receptor Structure Mechanism of Hormone Action Protein Hormones (cAMP second messenger) LH Receptor G Plasma Membrane

Adenylate Cyclase R C S-ER Protein Kinase A (PKA) Steroid Synthesis Mitochondria Nucleus Protein Synthesis (Enzymes) Synthesis R-ER Protein DNA Mechanism of Hormone Action

Protein Hormones (cAMP second messenger) LH G Receptor Plasma Membrane Adenylate Cyclase ATP cAMP S-ER cAMP R C Protein Kinase A (PKA)

Steroid Synthesis Mitochondria Nucleus Protein Synthesis (Enzymes) Synthesis R-ER Protein DNA Mechanism of Hormone Action Protein Hormones (cAMP second messenger) LH G Receptor

Plasma Membrane Adenylate Cyclase cAMP ATP R cAMP Protein Kinase A (PKA) S-ER Steroid Synthesis C (+ PO4) Mitochondria Histones Nucleus Protein Synthesis (Enzymes)

Synthesis R-ER Protein mRNA DNA Mechanism of Hormone Action Protein Hormones (cAMP second messenger) LH G Receptor Plasma Membrane Adenylate Cyclase cAMP Testosterone

ATP R cAMP Protein Kinase A (PKA) S-ER Steroid Synthesis C (+ PO4) Mitochondria Cholesterol Pregnenolone Cholesterol Protein Synthesis (Enzymes) Synthesis

R-ER Protein mRNA Histones Nucleus DNA Mechanism of Hormone Action Protein Hormones (cAMP second messenger) LH G Receptor Plasma Membrane Adenylate Cyclase cAMP

Testosterone ATP R cAMP Protein Kinase A (PKA) S-ER Steroid Synthesis C (+ PO4) Mitochondria Cholesterol Pregnenolone Cholesterol Protein Synthesis (Enzymes) Synthesis

R-ER Protein mRNA Histones Nucleus DNA cAMP Second Messenger Hormones Anterior Pituitary Hormones LH, FSH, Prolactin STH, ACTH, TSH Placental Hormones HCG, eCG Protein Hormones (Ca2+ Second Messenger)

Plasma Membrane Receptor GnRH G-protein PIP2 PLC Protein Kinase C R Ca2+ Secretory Granules Endoplasmic Reticulum

Plasma Membrane Protein Hormones (Ca2+ Second Messenger) Plasma Membrane Receptor GnRH G-protein PIP2 PLC Protein Kinase C R Ca2+ Secretory Granules

Endoplasmic Reticulum Plasma Membrane Protein Hormones (Ca2+ Second Messenger) Plasma Membrane Receptor GnRH G-protein PIP2 DAG PLC IP3 Ca2+

R Ca2+ Secretory Granules Endoplasmic Reticulum Plasma Membrane Protein Kinase C Protein Hormones (Ca2+ Second Messenger) Ca2+ Plasma Membrane Receptor GnRH G-protein

PIP2 DAG PLC IP3 Ca2+ R Ca2+ Secretory Granules Endoplasmic Reticulum Plasma Membrane Protein Kinase C Protein Hormones (Ca2+ Second Messenger) Ca2+

Plasma Membrane Receptor GnRH G-protein PIP2 DAG PLC IP3 Protein Kinase C Ca2+ R Ca2+

Secretory Granules Endoplasmic Reticulum Fusion Plasma Membrane LH Calcium Second Messenger Hormones GnRH triggers release of LH in anterior pituitary Oxytocin triggers contractions of smooth muscle PGF2

triggers apoptosis of cell inhibition of progesterone synthesis Steroid Hormone Action (Slow) Steroid (estrogen) Cell Membrane Diffusion? Change in Cell Physiology Cytoplasm Nucleus New Protein Receptor R-ER mRNA

Protein synthesis DNA Steroid Hormone Mechanism Estradiol Progesterone Testosterone, Dihydrotestosterone Cortisol Ca2+ Steroid Hormone (Fast) Estradiol (cAMP second messenger) Receptor G

Plasma Membrane Adenylate Cyclase cAMP ATP Ca R cAMP Protein Kinase A (PKA) 2+ C (+ PO4) Smooth Muscle Contraction (Uterine Myometrial Cell) Histones Nucleus Protein

Synthesis (Enzymes) Synthesis R-ER Protein mRNA DNA Steroid Hormone (Fast) Not the classical mechanism of action of a steroid hormone Requires plasma membrane receptor Operates via protein kinase activation Estradiol smooth muscle contraction of uterus Progesterone inhibits ion channels and thereby smooth muscle contraction of uterus, multiple kinases maybe involved

Hypothalamus Feedback Loops Neuro-secretory Cells Releasing Hormones Polypeptides Portal Vein - Anterior Pituitary Gonadotropins: FSH, LH Proteins Blood Stream Gonads Receptor on Cell Surface

only effects on [ Why ] target organs Cyclic AMP inside cell Steroid Hormone Production { Testosterone Estradiol Progesterone Blood Stream Bound to Protein Endocrine Feedback Loops Negative gonadal steriods Testosterone, Progesterone, Estradiol Protein hormones

inhibin Positive Gonadal steroids estradiol Chapter 5 of Textbook (Senger, 2012) Contains more than covered here Responsible for all material in book Also Handout 4 (found in lecture outline)