The regulation of testosterone formation in the Leydig cell.
Testosterone is formed from cholesterol substrate by luteinising hormone (LH). This hormone occupies a receptor site on the plasma membrane of the Leydig cell to activate adenylate cyclase, which in turn catalyses the formation of cAMP from ATP. cAMP then binds to the regulatory subunit of protein kinase, leading to activation of the cholesterol side-chain cleavage enzyme (P450scc) which is responsible for the conversion of cholesterol to pregnenolone. Other enzymes subsequently complete the synthesis of testosterone.
