THE ROLE OF NITRIC-OXIDE IN THE REGULATION OF ALDOSTERONE SYNTHESIS BY ADRENAL GLOMERULOSA CELLS

The role of nitric oxide (NO) in the regulation of aldosterone synthes is in the adrenal glomerulosa is not known. In this study, we observed that Liberators of NO such as S-nitroso-N-acetyl-penicillamine (SNAP) , sodium nitroprusside (Snp) and spermine nonoate (SNO) could signific antly inhibit angiotensin II (AII) and ACTH-induced aldosterone synthe sis in isolated rat and cultured human adrenal glomerulosa cells. To e valuate more precisely whether glomerulosa cells express NO synthase, we performed immunoblotting experiments with antibodies specific for t he endothelial type ecNO synthase as well as the neuronal NO synthase. This revealed the presence of the ecNO synthase in rat adrenal capsul es, in normal and in adenomatous human adrenal glomerulosa tissue, as well as in freshly dispersed rat adrenal glomerulosa cells. Furthermor e, on immunohistochemical analysis, rat adrenal glomerulosa cell secti ons showed strongly positive staining for ecNO synthase. These results suggest that NO may be an important negative modulator of adrenal glo merulosa steroidogenesis. (C) 1997 Elsevier Science Ltd.