SUPPRESSION OF PLASMA ENDOTHELIN-1 LEVEL BY ALPHA-HUMAN ATRIAL-NATRIURETIC-PEPTIDE AND ANGIOTENSIN-CONVERTING ENZYME-INHIBITION IN NORMAL MEN

The effect of synthetic alpha-human atrial natriuretic peptide (alpha- hANP) on plasma endothelin-1 (ET-1) level was examined in 6 healthy su bjects. Intravenous infusion of alpha-ANP (0.1 mug/kg/min) resulted in significant falls in plasma renin activity and aldosterone, but witho ut effect on ET-1 level. An angiotensin converting enzyme inhibitor, c aptopril, increased plasma renin activity and decreased aldosterone, r espectively. However, plasma ET-1 levels were not modified by captopri l. In cases with alpha-hANP infusion after captopril (25 mg, p.o.,), t he renin-angiotensin-aldosterone system was further inhibited compared with the first group, and ET- 1 at 60 min was significantly suppresse d from the baseline. These data suggest that alpha-hANP when combined with captopril brings about the suppression of plasma ET- 1 concentrat ions in men.