DIFFERENTIAL-EFFECTS OF ENDOGENOUS AND EXOGENOUS NITRIC-OXIDE ON THE RELEASE OF ENDOTHELIN-1 FROM THE INTACT PERFUSED RAT ADRENAL-GLAND IN-SITU

Studies using an inhibitor of nitric oxide (NO) synthesis have suggest ed that endogenous NO may have a role in regulating endothelin release , We investigated the effect of endogenous and exogenous nitric oxide (NO) on the release of irET-1. L-NAME stimulated, but L-arginine inhib ited irET-1 release, Perfusing sodium nitroprusside (SNP), however, di d not inhibit irET-1 secretion, CyclicGMP, the second messenger for NO action, was stimulated by SNP but not by L-arginine, These data demon strate that endogenous NO inhibits of irET-1, in a manner which is ind ependent of cGMP, and suggest that this action may contribute to the v asodilatory effect of NO.