Effects of Calcium and Theophylline on ACTH– and Dibutyryl Cyclic AMP—Stimulated Steroidogenesis and Glycolysis by Intact Mouse Adrenal Glandsin Vitro

Abstract

Exogenous calcium is required for both the steroidogenic and the glycolytic response to ACTH by intact mouse adrenal glands in vitro. By contrast, dibutyryl cyclic AMP—evoked steroidogenesis and glycolysis proceed efficiently in calcium—free medium as does the glycolysis induced by exogenous steroids. This suggests that exogenous calcium acts by enhancing the ACTHevoked synthesis of cyclic AMP or by preventing its destruction. The first alternative is favored since the phosphodiesterase inhibitor theophylline, used at 10 mM concentration, stimulated steroid production less effectively than calcium in the presence of ACTH, but more effectively than calcium in the absence of ACTH. Theophylline inhibited the glycolytic action of ACTH, dibutyryl cyclic AMP and exogenous steroids, denoting that its effects are not confined to the inhibition of phosphodiesterase. (Endocrinology92: 743, 1973)