Possible role of vascular angiotensin converting enzyme in the genesis of hypertension.

This study was designed to evaluate changes in angiotensin converting enzyme (ACE) activity in 2-kidney, 1-clip renal hypertensive dogs. Blood pressure increased and remained elevated for eight months after partial clamping of the left renal artery. Plasma renin activity was increased for one month after surgery, but then returned to the pre-clamping level. SA-446, a potent ACE inhibitor, reduced blood pressure in 8 M-hypertensive dogs. Plasma ACE activities was not altered during the course of hypertension, but vascular ACE activities in the pulmonary and mesenteric arteries and the aorta were significantly increased in 8 M-hypertensive dogs. These results may indicate that ACE plays an important role in the maintenance of chronic phase of 2-kidney, 1-clip renal hypertension and that suppression of vascular ACE activities might be a mechanism underlying the hypotensive effect of ACE inhibitors.