The Mechanisms of Luteinizing Hormone-Induced Activation and Desensitization of Adenylate Cyclase

Abstract

It is well established that LH interacts with its plasma membrane receptor to activate the adenylate cyclase system to form cyclic AMP followed by a subsequent increase in steroidogenesis. Repeated administration of the hormone leads to a desensitization of that same hormonal response and eventually to loss of receptors (down regulation). Recent evidence suggests that LH, may also directly activate other transducing mechanisms e.g. leading to activation of phospholipase A₂ and formation of arachidonic metabolites. Increases in intracellular calcium and possibly activation of protein kinase C also occur. Work in our laboratory is focused on the possible roles of these transduction mechanisms in the activation and desensitization of adenylate cyclase and the subsequent formation of the male androgen, testosterone.