Modulation of Adenylate Cyclase Activity in Liver and Fat Cell Membranes by Insulin

Science  25 Feb 1972:
Vol. 175, Issue 4024, pp. 906-908
DOI: 10.1126/science.175.4024.906


Insulin depresses both the activity of adenylate cyclase stimulated by glucagon, epinephrine, and sodium fluoride in liver cell membranes and the activity of adenylate cyclase stimulated by epinephrine and adrenocorticotropin in particulate preparations from homogenates of isolated fat cells. Significant inhibition is detected with very low concentrations (10-11 molar) of insulin but not with unphysiologically high (10-9molar) concentrations of the hormone. These direct effects of insulin on an enzymatic system in broken-cell -preparations suggest a fundamental role of adenylate cyclase activity and of cyclic adenosine monophosphate in the mechanism of action of insulin.