Endocrinology Summers

Hormones Endocrine Glands Receptors Homeostasis 2nd Messengers

Nuclear Receptors Genetic Regulation Hormone Synthesis Receptor Regulation Hypothalamo-Hypophysial Communication

Tropic Hormones Neurohypophysial Nonapeptides Thyroid Axis Steroids Adrenal Axis

Adrenal Medulla Osmotic-Pressure Balance Reproductive Endocrinology Prolactin Somatic Axis

Growth Factors Immune Factors Ca++, PO4 Homeostasis Pancreatic Hormones GI Hormones

Guts 'n Brains Brain Hormones Neurosteroids Neuropeptides Endocrine Evolution

Figures for Endocrionology text:Vertebrate Endocrinology5th Edition - David O. Norris: Read pages 1-7; 30-45 for this lecture acronyms    end

I. Introduction to Endocrine Function 			


	A. Endocrines = Hormones are endogenous chemicals produced by glands 


		1. Secreted into the Bloodstream


			a. no ducts


				i. exocrine glands have ducts to the outer surface


					(1) e.g. surface of the skin, lumen of the intestine,
					    uterine cavity


			b. plasma concentration [hormone] = the amount (often in
			    ng/ml) of hormone in the blood


		2. Exocrines, Paracrines, Autocrines, Neurotransmitters


			a. may be similar or identical to hormones but 
			   are not secreted into the blood


			b. Exocrines secreted outside the body


				i. pheromones, sweat, digestive enzymes


			c. Paracrines are secreted into the extracellular fluid


				i. effect adjacent cells


					(1) prostaglandins (PGs), growth factors (GFs),
					    thromboxanes (TX), leukotrienes, opiate peptides


			d. Autocrines are also secreted into the extracellular fluid


				i. effect the cells that secrete them


				ii. Autocrines usually = Paracrines


			e. Neurotransmitters are paracrines secreted into a specific type
			   of extracellular space = synaptic cleft

				i. DA, NE, Epi, ACh, GABA, Glutamate, histamine, glycine...


				ii. neurons which secrete into the blood stream are neurosecretory neurons


					(1) the secretion is a neurohormone


					(2) the synapse with the bloodstream is a neurohemal organ


			f. Growth Factors


				i. paracrine/autocrines which may mediate hormonal effects


					(1) NGF, EGFs, IGFs, PDGF, ILs


		3. Intracellular Endocrine Mediator = 2nd messenger


			a. stimulate cellular function as a result of hormones 
			   binding to membrane receptors


				i. cAMP, cGMP, Ca++, IP3, Calmodulin, protein kinases,
				    Phosphatidylcholine, polyamines, PGs, oligosaccharides