Simultaneous measurement of renin and renin substrate concentration in human plasma by a simple kinetic method.

A simple kinetic method is described for measurement of plasma renin concentration (PRC) and plasma renin substrate concentration (PRS) in human plasma. It is based on the radioimmunological determination of angiotensin I generated when a plasma sample is incubated at 37 degrees C for 2, 4, 6 and 8 h. The use of exogenous renin and renin substrate preparations are not required. The specific velocity constant of reaction (K) was used to deduce the PRC. PRS determination was based on the stoichiometric conversion of renin substrate to angiotensin I. PRC and PRS have been determined in plasma from healthy subjects, plasma from health subjects 3 h after oral furosemide administration and in plasma from women, 12-20 weeks normally pregnant.