Effects of unilateral nephrectomy on plasma renin substrate and renin concentration in rats

Effects of unilateral nephrectomy on plasma renin concentration and renin substrate (angiotensinogen) concentration were studied over an experimental period of 10 days in rats. The maximum increase in plasma renin substrate concentration after bilateral nephrectomy was 9 times higher than the preoperative level. Very low but measureable plasma renin concentrations were found in rats nephrectomized bilaterally 24 hrs previously. In unilateral nephrectomized rats the concentration of renin substrate in plasma increased maximumly 3.5-fold within 24 hrs after the operation and on the third day it was decreased to half of the maximum level. Even 10 days after uninephrectomy the concentration of plasma renin substrate was significantly higher than that of normal rats. Twenty four hours after unilateral nephrectomy plasma renin concentration decreased to similar low levels as those found in bilateral nephrectomized rats. The decreased concentration of plasma renin, however, returned to normal 3 days after uninephrectomy. The inverse relationship was seen between the concentrations of plasma renin and plasma renin substrate. However, substrate concentration in plasma rised faster and longer than plasma renin decreased.