To assess if dopaminergic control of aldosterone secretion is mediated by the renin-angiotensin system, the effect of chronic angiotensin converting enzyme inhibition by enalapril on the aldosterone response to metoclopramide has been studied in 10 patients with mild to moderate essential hypertension. Enalapril reduced supine blood pressure and increased the heart rate significantly. Plasma renin activity and urinary sodium excretion rose significantly. PRA was not changed by metoclopramide, neither during placebo nor during enalapril treatment. Metoclopramide induced a two-fold increase in plasma aldosterone, the peak response being reached within 15 min. Enalapril treatment did not alter the aldosterone response to metoclopramide. Dopaminergic control of aldosterone secretion appears to be independent of the renin-angiotensin system.