ACTION OF ADENOSINE ON STEROIDOGENESIS IN ISOLATED RAT ADRENOCORTICAL-CELLS

The regulatory role of adenosine in a number of tissues has been the subject of recent investigations [1, 5, 7, 14]. In adrenal tumour cells the nucleoside appears to stimulate adenylale cyclase at an external site in a manner that is antagonised by theophylline [14]. The present report describes a comparison of the effects of theophylline, adenosine and related compounds on steroid production by normal isolated adrenal cells. Neither adenosine or theophylline affected basal steroidogenesis over a wide concentration range. However both compounds markedly enhanced ACTH-stimulation of steroid production without increasing maximal output. The agents exhibited additive effects when used in combination, suggesting that they acted at a common site. It is proposed that in normal adrenal cells adenosine does not stimulate adenylate cyclase but inhibits cyclic-3',5'-AMP phosphodiesterase leading to increased steroid production in the presence of ACTH. These findings question the validity of using adrenal tumour cells as a model for studying the action of ACTH. © 1978.