INHIBITION OF PLASMA ENDOTHELIN-1 CONCENTRATION BY CAPTOPRIL IN PATIENTS WITH ESSENTIAL-HYPERTENSION

The aim of this study was to determine whether captopril has any effec t on plasma endothelin-1 (ET-1) concentration in patients with essenti al hypertension. Nine normotensives and eleven hypertensives were incl uded in this study. Blood pressure and pulse rate were monitored befor e and at 60 min after captopril ingestion (25 mg). Simultaneously, blo od samples for plasma ET-1 and plasma renin activity (PRA) determinati on were obtained. In the normotensives, captopril treatment resulted i n a significant rise in PRA, but without statistical changes in blood pressure and plasma ET-1. By contrast, in the hypertensives, although PRA elevated similarly after captopril, both blood pressure and plasma ET-1 decreased significantly compared with their respective preloadin g level. These data suggest that the blood pressure-lowering effect of captopril in essential hypertension may be at least in part, mediated by its inhibition of ET-1 production from the vascular endothelium.