Exaggerated response of renin secretion to captopril (SQ 14225) in renovascular hypertension.

Captopril (SQ 14225), an orally active converting enzyme inhibitor, was administered in a dose of 50 mg to 12 normotensive subjects (Group I), 26 essential hypertensive patients (Group II), and 8 renovascular hypertensive patients (Group III). In Group III, 5 of the 8 patients had control plasma renal activity (PRA) similar to those in Groups I and II patients, but the PRA response to the administration of captopril was greater in 7 of the 8 patients than those in Groups I and II. These 7 patients had either bilateral or unilateral main renal artery stenosis. Captopril caused no increase in PRA in the remaining 1 who had unilateral renal artery stenosis with contralateral renin aplasia. It is concluded that this provocation test is useful as a screening procedure for the diagnosis of renovascular hypertension.