Organ Hypothalamus Anterior Pituitary Posterior Pituitary Pineal Thyroid Parathyroid

Organ Hypothalamus Anterior Pituitary Posterior Pituitary Pineal Thyroid Parathyroid Stomach Adrenal Cortex Adrenal Medulla Pancreas Liver Kidney Adipose Small Intestine Large Intestine Ovaries Testes Placenta

Hormone(s) GHRH, TRH, GnRH, CRH, Dopamine(PIF), Somatostatin GH, TSH, LH, FSH, PRL, ACTH Oxytocin, ADH(AVP) Melatonin T3, T4, Calcitonin PTH Ghrelin Cortisol, Aldosterone, Corticosterone, Dehydroepialdosterone, Androstendione Norepinephrine, Epinephrine Insulin, Glucagon, PPY, Somatostatin IGF-1 Renin, 1,25-OH-D, EPO Leptin CCK, PYY PYY Estrogen, Progesterone, Relaxin (during pregnancy) Testosterone hCG, hCS, Estrogens, Progesterone, Relaxin

Only FREE hormones in blood can cause action – most bound to plasma proteins (↑↑ T½ , ↓↓ metabolic clearance)

Receptor

Mechanism

G-Protein Coupled

Hormone binds; α, β, γ complexes assoc. w/ recepter, activated via GDP→GTP; α subunit dissociates and binds with membrane-bound target to initiate intra-cellular signal

Enzyme-Linked

Homodimer; leptin binds to extracellular part; phosphorylation and activation of JAK2; causes phosphorylation of STAT; activates tx of gene, synthesis of protein; JAK2 activates other ez systems mediating rapid effects G-Protein coupled mechanism activates ATP→cAMP; activated cAMP dependent protein kinase; phosphorylates protein; get cell response G-Protein coupled mechanism activates PIP2→ IP3+DAG; activates protein kinase C; phosphrylates protein; cell response Diffuse into cell; bind cytoplasmic or nuclear receptor; hormone-receptor complex binds hormone response element on DNA; activates or inhibits tx, mRNA synth, protein synth

G-Protein Coupled generation of cAMP Second Messenger G-Protein Coupled IP3 and DAG Second Messenger Intracellular

Leptin receptor Peptide hormone Mech of angiotensin II vasoconstriction Steroid, T3, lipophilic hormones