Human cultured adrenal fasciculata-reticularis cells are targets for angiotensin-II: effects on cytochrome P450 cholesterol side-chain cleavage, cytochrome P450 17 alpha-hydroxylase, and 3 beta-hydroxysteroid-dehydrogenase messenger ribonucleic acid and proteins and on steroidogenic responsiveness to corticotropin and angiotensin-II.

Abstract

In the present study we have examined the effects of ACTH and angiotensin-II (A-II) on cultured human adult fasciculata-reticularis-specific functions. When cells were cultured in a chemically defined medium, the mRNA levels of cholesterol side-chain cleavage enzyme (P450scc), 17 alpha-hydroxylase/17,20-lyase (P45017 alpha), and 3 beta-hydroxysteroid dehydrogenase (3 beta HSD) progressively declined, so that by day 6 of culture, less than 20% of those observed in freshly isolated cells were present. ACTH and A-II, in a dose- and time-dependent manner, enhanced the mRNA levels of the three enzymes and the protein levels of P45017 alpha and 3 beta HSD, but not protein levels of P450scc. At maximal concentrations, the effects of ACTH on P450scc mRNA levels and P45017 alpha mRNA and protein levels were significantly greater than those induced by A-II, but the effects of both hormones on 3 beta HSD mRNA and protein were similar. At maximal concentrations, the effects of ACTH and A-II were additive only on 3 beta HSD mRNA and protein. The cortisol production of cells pretreated with ACTH or A-II was significantly higher than that of control cells, but the effects of ACTH were greater than those of A-II. Moreover, the acute steroidogenic responses to ACTH or A-II of cells pretreated with either hormone, were significantly higher than those of control cells. In conclusion, the present results demonstrate that human adult adrenal fasciculata-reticularis cells are targets for A-II, because 1) A-II acutely stimulates cortisol secretion and causes a long term increase in P450scc, P45017 alpha, and 3 beta HSD mRNA levels; 2) the steroidogenic responsiveness of A-II-pretreated cells to both ACTH and A-II was increased; and 3) the positive effects of A-II alone or in association with ACTH on steroidogenic enzyme gene expression are opposite those previously reported on bovine and ovine adrenal cells.