The role of protein kinase C in insulin signal transduction via adenylyl cyclase signaling mechanism

Activation of proteinkinase C with diacylglycerol or phorbol-12-myristate-13-acetate in the rat muscle membrane or Anodonta cygnea mollusc blocks the insulin stimulating signal to adenylyl cyclase via tyrosinekinase type receptor. The same occurs with stimulating effect of biogenic amines to adenylyl cyclase via serpentine type receptor. Transduction of the inhibitory signal induced with isoproterenol to adenylyl cyclase remained unchanged in case of the proteinkinase C activation. The findings suggest that phorbol-sensitive proteinkinase C realizes a negative regulation of insulin-sensitive adenylyl cyclase signalling system. This negative regulation might prove a universal mechanism of the adenylyl cyclase system desensitisation.