Stimulation of Steroid C–11β Hydroxylation in Adrenal Mitochondria by Cyclic 3′,5′-Adenosine Monophosphate

Abstract

ADENOSINE-3′,5′-monophosphate (cyclic 3 ′,5′-AMP) has been shown to stimulate steroid C–11β hydroxylations in rat adrenal homogenates¹ as well as the production of corticosterone from endogenous precursors in surviving rat adrenal sections². In the latter instance, the effect of the cyclic nucleotide appeared to be related to enhancement of α-glucan phosphorylase activity³, consequent NADPH production, and, possibly, to increased provision of endogenous steroid substrate⁴. In homogenates, however, stimulation of steroid C–11β hydroxylation did not seem to be dependent on glycogen phosphorylation, NADPH generation, or the availability of endogenous precursors⁵. Since steroid C–11β hydroxylase activity is associated with adrenal mitochondria⁶, experiments were undertaken to determine whether cyclic 3′,5′-AMP was effective in isolated mitochondria. The data presented here reveal that the cyclic nucleotide was capable of stimulating C–11β hydroxylation of added progesterone and 11-deoxycorticosterone in purified adrenal mitochondria fortified with NADPH.