Effect of blockade of angiotensin-I converting enzyme on the blood pressure of renal hypertensive rabbits

A peptide converting enzyme inhibitor given intravenously to rabbits was shown to abolish the pressor response to injections of rabbit renin and of angiotensin-I and to augment the depressor response of bradykinin. In rabbits with acute two-kidney Goldblatt hypertension (2-KGH [one renal artery clamped, the other intact]) a total dose of 36 mg/kg infused for one hour lowered the blood pressure but not to a normal level. One week after removal of the intact kidney (acute one-kidney Goldblatt hypertension [1-KGH]) infusions of the peptide were still antihypertensive. Thirty to 60 days after removal of the intact kidney (chronic 1-KGH) the decapeptide had no antihypertensive effects. It is suggested that in the first two models hypertension is dependent on the renin-angiotensin system (RAS), but not in the chronic 1-KGH animal. Since the response to the new agent is not species specific and is well tolerated, it may become a valuable tool in investigating the role of the RAS in various forms of clinical hypertension.