Assay of Renin in Peripheral Blood

Abstract

A modification of Helmer's method for the determination of renin in peripheral blood was described. It consists of incubation of blood plasma at 37°C for 2 hours at pH 5.5, extraction of angiotensin released during the incubation by the action of renin, final purification of the extracted angiotensin by ion-exchange resin Dowex-50 chromatography, and bioassay of the purified angiotensin on the rat blood pressure preparation. The sensitivity, specificity, reproducibility, and accuracy in this method were studied, and they proved fairly satisfactory. The method will be useful in studying the renin-angiotensin system in human being. Circulating renin was found increased in patients with secondary aldosteronism, whether hypertensive or not. This finding supports the hypothesis that the renin-angiotensin system has a marked and specific stimulatory effect on the secretion of aldosterone.