Abstract
Estimation of the renin concentration in human plasma is of increasing importance in the clinical evaluation of hypertensive disease. In this study, fundamental experiments have been made on the estimation of plasma renin activity (PRA) using radioimmunoassay technique for angiotensin I.
A linear generation slope was found during first 2 hours incubation and slightly decreasing slope after 2 hours. Concerning the correction for the nonspecific effects of“angiotensin I-like protein”, a comparison was made between the method to subtract PRA of unincubated samples and that to use boiled supernatant. There was no significant difference between PRA obtained by these two methods.
Normal values were obtained from 7 male and 8 female normal subjects on unrestricted diet. Normal male had mean and standard deviation of 0.9±0.5 ng/ml/h at rest. 1.8±0.8ng/ml/h on upright posture. Normal female in follicular phase had 0.5±0.3 ng/ml/h at rest, 1.3±0.7 ng/ml/h on upright, while those in luteal phase had 1.8±0.7 ng/ml/h at rest, 3.3±0.6 ng/ml/h on upright. There was significant difference between PRA in follicular phase and that in luteal phase in each of the postures (p<0.005 respectively.) The response of PRA to combined stimula of intravenously injected Furosemide (20 mg) and ambulation was determined in two normal male sub jets. The response was more than three times the base, reaching plateau after 1 hour of the stimula. This technique seemed to be convenient for routine PRA examination.
