ABSTRACT
The renin angiotensin system is present in both circulating and tissue forms. Its ultimate product, angiotensin II, is among a diversity of substances that control blood pressure. In the present work, comparison between valsartan [AT[1] antagonist] and benazepril and captopril [ACE inhibitors] revealed the following: Valsartan [15 mg/kg/day], captopril [15 mg/kg/day] and benazepril [3 mg/kg/day] p.o. for 4 weeks in renovascular hypertensive rats induced significant reduction in systolic blood pressure starting from the first week of treatment. There was no significant difference among the three groups except in the fourth week when captopril and benazepril groups were significantly different from valsartan group. In isolated rabbit aorta, all the three drugs reduced the force of angiotensin-I induced contraction, significantly for valsartan and captopril and insignificantly for benazeprilat