Hormone Action on Liver Adenyl Cyclase Activity

摘要: Adenyl cyclase activity was measured by conversion of [32P]ATP to adenosine 3′:5′-cyclic [32P]phosphate in a washed particle suspension from mouse and rat liver. The test contained an ATP regenerating system 10 mM unlabeled Ado-3′:5′-P trap the labeled formed. Decreased activities were observed when methyl xanthines used place Ado-3′:5′-P. reaction stimulated Mg++ which increased Vmax without changing apparent Km towards ATP. synthetic glucagon over range 0.1–20 μg/ml. Removal Ca++ ethylene glycol-bis-(β-amino-ethyl ether)-N,N'-tetraacetic acid (EGTA) strongly augmented action, while 1 inhibitory. data suggest enhanced transmission hormone signal (hypothetical) receptor catalytic enzyme unit chelation membrane bound calcium. In contrast hyperbolic dose response curve with glucagon, fluoride (1–10 mM) sigmoidal shape, effect being inhibited pyrophosphate. Although inhibition observed, EGTA did not augment fluoride. effects at maximal concentrations additive, indicating stimulation same adenyl system.