Study of renovascular hypertension in rat. II. Effects of converting enzyme inhibitor (captopril) in the acute and chronic stages of two-kidney one-clip Goldblatt hypertension in rat.

Two-kidney, one-clip Goldblatt models were produced in Wistar rats by placing a stenotic clip around the left renal artery. The animals were classified into three groups according to the time when captopril was started. In group 1 rats captopril was begun on the day following the operation and was continued for 6 weeks. During this period hypertension did not develop. In group 2 in which captopril was started 4 weeks after placement of the renal arterial clip, the blood pressure remained high as late as 12 weeks despite of continued administration of the drug. However, in group 3, captopril which was started 12 weeks postoperatively was very effective in correcting high blood pressure. In the sham operated group the blood pressure was unchanged by captopril administration. These results suggest that the role of renin-angiotensin system seems to vary according to the stages of experimental hypertension and that at least in the acute and chronic stage of two-kidney one-clip Goldblatt hypertension angiotensin II may play a major role in initiation and maintenance of high blood pressure.