Evaluation of hypotensive mechanisms of Captopril in addition to its inhibition of the converting enzyme in spontaneously hypertensive rats.

In spontaneoulsy hypertensive rats (SHR), the hypotensive effect of captopril (30 mg/kg/day per os for 4 days), which inhibits the converting enzyme when given orally was significantly potentiated rather than suppressed by aprotonin (100,000 KIU/day s.c. for 7 days), but was not affected by indomethacin. These findings suggest that neither the kallikrein-kinin system nor the prostaglandin system is involved in any of the hypotensive actions of captopril in SHR other than the inhibition of the converting enzyme.