Improved Method for Measurement of Renin Activity in Human Plasma

Abstract

A simple and sensitive method for the measurement of plasma renin activity is described. The method consists of prolonged incubation (16 hours) of 2.0-3.0 ml of plasma at 37.5°C, pH 5.5, with small amounts of both ethylenediamine tetra-acetic acid and diisopropyl-fluorophosphate, purification of produced angiotensin with Dowex 50 AV-X4(H⁺) column chromatography, and bioassay on rat blood pressure. The recovery rate of added synthetic angiotensin II was 92.0±5.3% (s. n.). Plasma renin activity in 30 normal subjects ranged from 3.0 to 17.0 ng angiotensin equivalent per nil plasma. These values were significantly elevated in 6 cases of renovascular hypertension (20-84 nglml), in a case of interruption of the aorta (35 ng/ml), and in a case of malignant hypertension (80 ng/ml), while in 3 cases of primary aldosteronism they were suppressed to subnormal levels (2.0-2.3 ng/ml).
The present method is easily applicable in ordinary clinical laboratories.