Changes of plasma renin, angiotensin II and renin substrate during reversal of malignant renovascular hypertension.

The relationship between plasma renin activity (PRA), angiotensin II (AT II) and renin substrate concentration (PRS) were studied in a patient with left renal artery occlusion and malignant hypertension before and after left-side nephrectomy. Initially, PRA and AT II were grossly elevated, while PRS was low. Treatment with alpha-methyl-DOPA and saline led to a fall in PRA and AT II and a large rise in PRS. The correlation between PRA and AT II (r=0.937; n=9, p less than 0.001) was highly significant. PRA and PRS were negatively correlated before operation (r=-0.78; n=6; p less than 0.05). A comparison of changes in PRS before and after nephrectomy suggests that renin substrate formation was increased when the ischemic kidney was still in situ. Following nephrectomy, PRA and blood pressure fell to normal within 5 hours, while PRS remained unchanged for this period of time. A two-compartmental analysis of the renin disappearance curve after nephrectomy revealed the presence of a fast and slow component with half-lives of 10 and 95 min, respectively.