Interaction of Cyclic AMP Derivatives with the Angiotensin II Receptor

Abstract

The effect of cyclic AMP and of its derivatives was studied on ¹²⁵I-angiotensin II and ¹²⁵I- (Sar¹, Ala⁸) -angiotensin II binding to rat adrenal membrane receptors. Dibutyryl cyclic AMP, 8-bro-mo-cyclic AMP and cyclic AMP inhibited both agonist and antagonist binding in a specific and dose-dependent way, with K₁ of 1.3 mM, 6.8 mM and about 30 mM, respectively. Scatchard analysis of binding data indicated that the nucleotides interacted directly with the membrane receptor for angiotensin II. These results suggest that cyclic AMP may act extracellularly and affect receptor-mediated events.