Abstract
Angiotensin II antagonist (AIIA, 1-Sar-8-Ala-Angiotensin II) in the range from 0.5 to 5.0 tcg/ kg/min was infused to 27 patients with chronic renal failue (CRF) who received hemodialysis to investigate the role of plasma renin activity (PRA) in manintaining blood pressure. 1. In six out of seven cases of high renin group with PRA value above 3.0 ng/ml/hr in the control period, a remarkable hypotensive effect was observed, lowering the systolic pressure by 18-30 mmHg. This hypotensive effect had no relation to the blood pressure of the control period. At the end of infusion, PRA increased about 1.7 times while plasma aldosterone concentration (FAG) decreased to half of the control value. 2. In nine out of 16 cases of normorenin group with PRA value 1.0-2.9 ng/ml/hr, a distinct hypotensive effect was observed lowering the pressure by 15 mmHg and over. PRA value was 2.0+0.6 (Mean+S. D.) ng/ml/hr in the control period. After AIIA infusion PRA increased and FAG decreased, and this result was similar to high reamn group. In other seven cases, which showed little change in blood pressure, PRA value was 1.4±0.4 ng/ml/hr in the control period and exhibited no notable change during AIIA infusion. However, PAC values were varied and did not indicate a specific trend. 3. In two out of four cases of low renin group with PRA value less than 1.0 ng/ml/hr, blood pressure slightly elevated by AIIA infusion. In other two cases, blood pressure showed no change. On the other hand, as in normorenin group PAC values varied and did not show any trend. 4. A negative correlationship was observed between PRA in the control period and maximum rate of the systolic pressure during the AIIA infusion. 5. A positive correlationship existed between PRA in the control and recovery period. The relationship, however, diminished as the amount of AIIA infusion was increased. From the above results, we conclude that in CRF patients PRA levels exceeding 2.0 ng/ml blood pressure is maintained by the renin-angiotensin system whether high or low. At the same time, the FAG level also depends mainly on the renin-angiotensin system.
