BIOS 213 Lecture Notes - Lecture 15: Globulin, Catecholamine, Adrenal Medulla
Document Summary
Hor(cid:373)o(cid:374)e: fu(cid:374)(cid:272)tio(cid:374) is to (cid:272)o(cid:373)(cid:373)u(cid:374)i(cid:272)ate (cid:862)sig(cid:374)al(cid:863) a (cid:272)he(cid:373)i(cid:272)al sig(cid:374)al sele(cid:272)ted (cid:271)y (cid:272)ells or gla(cid:374)ds (groups of cells) into blood. Target cells are distant from the cells that released them. Response to binding receptors varies from changing ion flux to dna transcription: unique to hormones tend to act slower. Amine hormones, modified from tyrosine, the amino acids. Catecholamines (epinephrine, norepinephrene): released from the adrenal medulla, 5 times more epinephrine than ne. Inactivation by enzymes terminates hormones influence, but unlike neurotransmitters effect may endure. Solubility ensures rapid access to the panic enzymes for inactivation. Intracellular enzymes if hormone receptor unit is taken into cell. Rapid release after the endocrine cell has been stimulated because they can be stored in vesicles (not lipid permeable) Most use a g-protein camp signal transduction system. Receptor-hormone complex activates g-protein (receptor bound to a hormone) G-protein subunit activates 2nd messenger system, an intracellular signal molecule, camp.
