Exogenous steroids alter steroidogenesis in cultured Y-1 adrenal tumor cells by actions preceding cyclic AMP

Using cultured Y-1 mouse adrenal tumor cells which produce 20 alpha-hydroxy-4-pregnen-3-one (20-DHP), it was found that 0.01 mM corticosterone and deoxycorticosterone increased basal and inhibited ACTH-induced 20-DHP production during consecutive 30 and 120 min incubations. Steroid effects were concentration-dependent and reversible. Six other steroids tested did not stimulate 20-DHP production and varied in ability to inhibit ACTH-stimulated steroidogenesis. Experiments demonstrated that 20-DHP production following treatment with cholera toxin, N,0'-dibutyryl cyclic AMP (dbcAMP), or pregnenolone was not inhibited by exogenous steroids. Corticosterone (0.01 mM) increased basal and inhibited ACTH-induced intracellular cyclic AMP (cAMP) production. Cytochalasin D, a microfilament perturbing agent, inhibited steroid-stimulated 20-DHP production, suggesting that ACTH and steroid stimulation mechanisms were similar. These findings taken together suggest that exogenous steroids can alter steroidogenesis by modifying plasma membrane adenylate cyclase activity.