Half life of circulating renin under different experimental conditions

The half-life of circulating renin was studied in normal rats and in rats with a single kidney that was ischemic. The resulting disappearance curve represented the sum of two exponentials. The average half-life of the fast component was 11.5 min for normal rats, 11 min for rats with mild renal ischemia, and 8 min for rats with severe renal ischemia. The mean half-life of the slow component was 67 min in normality, 84 min in mild ischemia, and 121 min in severe ischemia. Also, the calculated proportion of the slower component was different for each group, 60.3% in normality, 68.2% in mild ischemia, and 82.2% in severe ischemia. The results suggest that more than one kind of renin may be produced and released by the kidney, and also that renal ischemia may modify the normal metabolism of renin.