Alpha-human atrial natriuretic polypeptide inhibits steroidogenesis in cultured human adrenal cells

The ability of synthetic alpha-human atrial natriuretic polypeptide-(1-28) (alpha hANP) to alter steroidogenesis by human adrenal glands was investigated in primary human adrenal cell cultures. alphahANP (10(-9)-10(-7) M) inhibited basal and ACTH (10(-8) M)-stimulated aldosterone, cortisol, and dehydroepiandrosterone (DHEA) secretion in a dose-dependent manner. alpha hANP inhibited aldosterone (IC50, 1.3 X 10(-8) M) and cortisol (IC50, 0.7 X 10(-8) M) secretion more potently than it did DHEA (IC50, 7.5 X 10(-8) M) secretion. ACTH dose-dependent (10(-10)-10(-8) M) increases in aldosterone, cortisol, and DHEA secretion were significantly inhibited by alpha hANP (10(-8) M). In addition, alpha hANP enhanced the accumulation of intracellular cGMP in a dose-dependent manner. As aldosterone, cortisol, and DHEA secretion from cultured human adrenal cells was inhibited by alpha hANP, the site of inhibition of steroidogenesis by alpha hANP is probably localized in the early pathway of steroidogenesis in human adrenal cells. The results also suggest a link between inhibitory effects of alpha hANP and accumulation of intracellular cGMP.