Abstract
Very little has been known of the biochemical function of a human adrenocortical carcinoma cell line, SW-13. In this study, the production of several adrenal steroids and 3', 5'-cyclic adenosine monophosphate (cAMP) were investigated in this cell line. The cells were iucubated in L-15 medium containing 0.1% bovine serum albumin with several reagents in an atmosphere of 5% CO2 and 95% air for 2 hours at 37°C. Aldosterone (Ald), corticosterone (B), cortisol (F), dehydroepiandrosterone sulfate (DHEA-S) and cAMP were simultaneously assayed by specific radioimmunoassays in the medium and cells. Significant increases in cAMP production were observed by cholera toxin (10ng/ml) and forskolin (10nM), both direct stimulators of adenylate cyclase, in the cAMP concentration without an increase in the steroids. The DHEA-S concentration in the medium was significantly increased by angiotensin-II (10-7M), noradrenalin (3×10-5M), adrenalin (3×10-5M) or α-melanocytestimulating hormone (α-MSH, 10-7M), none of which was associated with cAMP production. Neither adrenocorticotropin (10-10M) nor human chorionic gonadotropin (500mIU/ml) stimulated the release of the steroids or cAMP production. A calcium ionophore, A23187 (10-7M), and 12-O-tetradecanoylphorbol-13-acetate (10-8M), a direct stimulator of protein kinase C, stimulated the release of DHEA-S, but not those of Ald, B and F. The results suggest that SW-13 retains functioning adenylate cyclase which, however, is not linked with steroidogenesis and that DHEA-S is produced probably by the mechanisms which involve protein kinase C system or calcium ion. This report provides the first demonstration of cAMP and DHEA-S production in SW-13 and suggests that this cell line is potentially useful for investigating the mechanisms of steroidogenesis in the human adrenal cortex.
