Studies on the active and inactive renin in renovascular hypertension

Active and inactive plasma renin concentrations (ARC and IRC) from both renal veins and the femoral artery, and the molecular weight (MW) of active and inactive renin (AR and IR) from both renal veins were measured in 6 patients with renovascular hypertension due to unilateral renal artery stenosis. Venous ARC on the affected side was higher than that on the unaffected side and arterial ARC. In 4 patients ARC increased and IRC decreased after circulating through the stenotic kidney, while in the other 2 cases venous IRC on the stenotic side was higher than arterial IRC. The MW of AR on the stenotic and non-stenotic sides were 40000-48000 and 45000-48000, respectively, and those of IR varied from 45000-53000 and 48000-55000, respectively. These values seem to be smaller than those of normal subjects. The renin molecule may be small immediately after the release from the kidney and become larger in the circulation. In 3 cases, whose ARC increased and IRC decreased after passing through the stenotic kidney, AR and IR from the stenotic kidney were smaller than those from the non-stenotic kidney. Some mechanism of AR and IR molecule reduction may work in the stenotic kidney to activate IR.