MEASUREMENT OF PLASMA-RENIN CONCENTRATION USING EXOGENOUS HUMAN RENIN SUBSTRATE IN NORMAL SUBJECTS - CORRELATION WITH PLASMA-RENIN CONCENTRATION AND PLASMA-ALDOSTERONE CONCENTRATION

Measurement of plasma renin concentration (PRC) was done in normal subjects at rest and under acute stimulation of renin release under unrestricted sodium intake. Concurrent measurements of plasma renin activity (PRA) and plasma aldosterone concentration (PA) were carried out. The mean values of PRC at rest and after stimulation of renin release were 12.8 ± 1.3 (SEM) and 21.7 ± 4.4 (SEM) ng AT I/ml/h, respectively. These corresponded to renin contents of 3.4 ± 0.34 (SEM) x 10-5 Goldblatt units and 5.8 ± 0.36 (SEM), respectively. The mean percent increase of PRC (82.1 ± 19.3 (SEM) %) was almost indentical to that of PA (81.5 ± 16.4 (SEM) %), but differed from that of PRA (269 ± 83.1 (SEM) %). A very high correlation between concurrent PRC and PA (r = 0.92, P = 0.001) was found in normal subjects at rest and under acute stimulation of renin release. A good correlation between PRC and PRA (r = 0.85, P = 0.001) was also observed. However, a higher correlation between percent increases of PRC and PA (r = 0.92, P = 0.001) than that of PRA and PA (r = 0.80, 0.01 = P = 0.005) was found. Results show that PRA is a good index of the renin content in plasma in normal subjects at rest and PRC reflects actual renin concentration in plasma at rest as well as under stimulation of renin release. © 1979, The Japanese Circulation Society. All rights reserved.