ATRIAL-NATRIURETIC-PEPTIDE INHIBITS THE PRODUCTION AND SECRETION OF ENDOTHELIN FROM CULTURED ENDOTHELIAL-CELLS - MEDIATION THROUGH THE C-RECEPTOR

Atrial natriuretic peptide (ANP) and endothelin-1 (ET-1) are vasoactive peptides produced in cells of the cardiovascular system. We examined the effects of ANP on ET-1 transcription, production (translation), and secretion in cultured bovine aortic endothelial cells (BAEC). ANP and C-ANP 4-23 (a specific ligand for the C or non-guanylate cyclase receptor) equipotently inhibited the synthesis of prepro-ET-1 and ET-1 proteins in BAEC by at least 50%. Both of these forms of ANP and another C receptor specific ligand, nanopiperazine ANP (11-15)-NH2, inhibited ET-1 secretion by as much as 55%. LY 83583, an inhibitor of ANP-induced cGMP generation, failed to reverse the ANP-induced inhibition of ET-1 secretion. This further indicated that the guanylate cyclase-linked B receptor is not involved. The decreased ET-1 secretion caused by C-ANP 4-23 was reversed by 8-bromo-cAMP or amiloride, which prevents ANP-induced inhibition of cAMP. We also found that ANP and C-ANP 4-23 augmented ET-1 mRNA levels in BAEC by prolonging the mRNA half-life. ANP or cycloheximide comparably inhibited ET-1 translation while increasing ET-1 mRNA levels, suggesting that the two events are related. These results indicate that ANP inhibits ET-1 protein production and secretion while stabilizing the ET-1 mRNA. The effects of ANP are mediated through the C receptor and are probably the result of ANP inhibiting the generation of cAMP. These findings suggest a potentially important new function for this receptor to mediate, in part, the interactions of ANP and ET in the vasculature.