1. Mechanism of Hormone Action

3. Receptor Structure

4. Mechanism of Hormone Action Receptor Protein Kinase A (PKA) Nucleus DNA Protein Synthesis (Enzymes) Plasma Membrane Protein Hormones (cAMP second messenger) Protein Hormones (cAMP second messenger) C R R-ER Protein Synthesis Mitochondria S-ER Steroid Synthesis LH G Adenylate Cyclase

5. Mechanism of Hormone Action Receptor Protein Kinase A (PKA) Nucleus DNA Protein Synthesis (Enzymes) Plasma Membrane Protein Hormones (cAMP second messenger) Protein Hormones (cAMP second messenger) G Adenylate Cyclase C R cAMP LH ATP cAMP C R R-ER Protein Synthesis Mitochondria S-ER Steroid Synthesis

6. C R cAMP Mechanism of Hormone Action Receptor Protein Kinase A (PKA) Nucleus DNA Histones Protein Synthesis (Enzymes) Plasma Membrane Protein Hormones (cAMP second messenger) Protein Hormones (cAMP second messenger) G Adenylate Cyclase LH ATP cAMP (+ PO 4 ) R-ER Protein Synthesis Mitochondria S-ER Steroid Synthesis mRNA

7. Mechanism of Hormone Action Receptor Protein Kinase A (PKA) Nucleus DNA Histones Protein Synthesis (Enzymes) mRNA Plasma Membrane Protein Hormones (cAMP second messenger) Protein Hormones (cAMP second messenger) Cholesterol G Adenylate Cyclase C R cAMP LH ATP cAMP (+ PO 4 ) R-ER Protein Synthesis Mitochondria Cholesterol Pregnenolone S-ER Steroid Synthesis Testosterone

8. Mechanism of Hormone Action Receptor Protein Kinase A (PKA) Nucleus DNA Histones Protein Synthesis (Enzymes) mRNA Plasma Membrane Protein Hormones (cAMP second messenger) Protein Hormones (cAMP second messenger) Cholesterol G Adenylate Cyclase C R cAMP LH ATP cAMP (+ PO 4 ) R-ER Protein Synthesis Mitochondria Cholesterol Pregnenolone S-ER Steroid Synthesis Testosterone

9. cAMP Second Messenger Hormones Anterior Pituitary Hormones » LH, FSH, Prolactin » STH, ACTH, TSH Placental Hormones » HCG, eCG

10. Protein Hormones (Ca 2+ Second Messenger) PLC Endoplasmic Reticulum Ca 2+ Protein Kinase C Plasma Membrane GnRH Receptor G-protein R Plasma Membrane Secretory Granules PIP 2

11. Protein Hormones (Ca 2+ Second Messenger) PLC PIP 2 Endoplasmic Reticulum Ca 2+ Plasma Membrane GnRH Receptor G-protein R Plasma Membrane Secretory Granules PIP 2 Protein Kinase C

12. Protein Hormones (Ca 2+ Second Messenger) PLC PIP 2 Endoplasmic Reticulum Ca 2+ Protein Kinase C Plasma Membrane GnRH Receptor G-protein DAG IP 3 R Ca 2+ Plasma Membrane Secretory Granules R PIP 2

13. Protein Hormones (Ca 2+ Second Messenger) PLC PIP 2 Endoplasmic Reticulum Ca 2+ Protein Kinase C Plasma Membrane GnRH Receptor G-protein DAG IP 3 R Ca 2+ Plasma Membrane Ca 2+ Secretory Granules R PIP 2

14. Protein Hormones (Ca 2+ Second Messenger) PLC PIP 2 Endoplasmic Reticulum Ca 2+ Protein Kinase C Plasma Membrane GnRH Receptor G-protein DAG IP 3 R Ca 2+ Plasma Membrane Ca 2+ LH Fusion Secretory Granules R PIP 2

15. Calcium Second Messenger Hormones GnRH » triggers release of LH in anterior pituitary Oxytocin » triggers contractions of smooth muscle PGF 2  » triggers apoptosis of cell » inhibition of progesterone synthesis

16. Steroid Hormone Action Cytoplasm Cell Membrane DNA Receptor Nucleus Steroid (estrogen) Diffusion? mRNA R-ER Protein synthesis New Protein Change in Cell Physiology

17. Steroid Hormone Mechanism Estradiol Testosterone, Dihydrotestosterone Cortisol

18. Feedback Loops Hypothalamus Releasing Hormones Neuro-secretory Cells Portal Vein Anterior Pituitary Gonadotropins: FSH, LH Blood Stream Gonads Receptor on Cell Surface Cyclic AMP inside cell Steroid Hormone Production Blood Stream - - Polypeptides Proteins Why only effects on target organs [ ] { Testosterone Estradiol Progesterone Bound to Protein

19. Endocrine Feedback Loops Negative » gonadal steriods – Testosterone, Progesterone, Estradiol » Protein hormones – inhibin Positive » Gonadal steroids – estradiol