Inactive renin in peritoneal fluid of the cat: responses to acute stimuli which alter plasma renin.

Active and inactive renin in plasma and peritoneal dialysate were studied in pentobarbitone anesthetized cats during 8 hours of peritoneal dialysis. In control cats, despite a significant rise in plasma active renin from 1.3 +/- 0.22 to 4.4 +/- 0.76 pmoles AI/ml/hr over 8 hours, plasma inactive renin was unchanged. Four-fold rises in plasma active renin after hemorrhage (15 ml/kg) and captopril (1 mg/Kg I.V.) were unaccompanied by significant change in inactive renin. Bilateral nephrectomy resulted in undetectable plasma active renin after 3 hours but plasma inactive renin was 25-30% of initial levels 6 hours post-nephrectomy. In peritoneal dialysate, active renin remained low in control cats but there was a ten-fold rise of inactive renin from 0.06 +/- 0.02 to 0.60 +/- 0.07 pmoles AI/ml/hr. After hemorrhage there was a slight rise of active renin after 3 and 4 hours. Inactive renin was lower than control 6 hours after nephrectomy and captopril, but higher than control 1 and 2 hours after hemorrhage. Dialysate inactive renin accumulation slopes were not different among treatments. Acute changes in plasma active renin have little effect on peritoneal dialysate renin.