Studies on cyclic nucleotides in the adrenal gland. X. Effects of adrenocorticotropin and prostaglandin on adenylate cyclase activity in the adrenal cortex.

Effects of ACTH and prostaglandin E1 (PGE1) on adenylate cyclase activities in the zona glomerulosa (the capsular fraction) and the zona fasciculata-reticularis (the decapsulated fraction) from rat adrenocortical glands have been studied. Stimulation by ACTH of adenylate cyclase activity was observed in both the capsular and decapsulated fractions in a similar dose-dependent manner. PGE1 only stimulated adenylate cyclase activity in the capsular fraction. The maximal stimulations induced by ACTH and PGE1 were additive on the capsular enzyme. A prostaglandin antagonist, polyphloretin phosphate failed to inhibit ACTH stimulation of adenylate cyclase at a concentration which completely blocked the effect of PGE1. [3H]PGE1 bound to subcellular fractions of both the capsular and decapsulated fractions of the gland. These results suggest that the capsular fraction possesses receptors for PGE1 coupled to the adenylate cyclase system which are distinct from those for ACTH. On the other hand, PGE1 receptors in the decapsulated fraction seem not to be coupled to the adenylate cyclase system.