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.