Enzyme immunoassay of angiotensin II in human plasma

We established a highly sensitive double-antibody enzyme immunoassay (EIA) for angiotensin (ANG) II. For competitive reactions, the ANG II-antibody was incubated with ANG II standard (or sample) and beta-D-galactosidase-labeled ANG III (delayed addition). Free and antibody-bound labeled antigen were separated using an anti-rabbit immunoglobulin G (IgG) coated immunoplate. The enzyme activity on the plate was fluorometrically determined. The present immunoassay allows detection of 0.4 to 72 fmol/well of ANG II. Using the present EIA, ANG II-like immunoreactivity (-LI) in human plasma was determined. The level of ANG II-LI in human plasma from 10 healthy volunteers was 33.3 +/- 10.4 pmol/l.