Studies with the Radioimmunoassay for Angiotensin II, and Its Application to Measurement of Renin Activity

Abstract

The radioimmunoassay for angiotensin II which we previously described has been revised, improved and simplified. Plasma angiotensin II concentration in normal subjects on unrestricted sodium intake averages 21±10 μμg/ml. The method may be applied to measurement of renin activity, giving average values of 0.73±0.32 U/ml plasma in normal subjects. Variation in sodium intake, activity and the administration of diuretics in normal subjects produce expected changes in both circulating angiotensin and renin activity. Anephric subjects show absent circulating angiotensin and very low but measurable renin activities.