Persistence of the steroidogenic effect of adenosin-3',5'-monophosphate in vitro: evidence for a third factor during the steroidogenic effect of ACTH.

Abstract

When added simultaneously with CAMP (adenosine-3′,5′-monophosphate), inhibitors of protein synthesis block the steroidogenic effect of CAMP in rat adrenal sections in vitro. However, after prior stimulation of adrenal sections by CAMP for 10–30 min, heightened rates of steroidogenesis persist despite removing CAMP from the medium and/or adding cycloheximide or chloramphenicol. This previously established steroidogenic effect continues undiminished for 30–40 min, and then decays with a half-life of about 25 min. Virtually identical results are obtained when ACTH is employed as the stimulator, and this is compatible with the hypothesis that CAMP is the intracellular mediator of ACTH action. Since aminoglutethimide, an inhibitor of cholesterol side chain cleavage, largely blocks the persistent steroidogenic effect of CAMP, the latter effect cannot be explained by an accumulation of steroid precursors beyond this important step in steroid biosynthesis. Thepresent findings indicate that the steroidogenic effec...