Radioimmunoassay of plasma renin activity.
We describe a sensitive, simplified radioimmunoassay method for determination of plasma renin activity. Plasma was acidified to the optimal pH (6.0) of angiotensin l generation with the least possible dilution, by using a single addition of hydrochloric acid and the enzyme inhibitor hydroxyquinoline. Recovery of unlabeled angiotensin l added to plasma was 92-97%; that of monoiodinated angiotensin l exceeded 90%, indicating satisfactory protection from proteolytic enzymes. Plasma constituents interfered little with the radioimmunoassay. Bland values for plasma kept at 0 degrees C were 10.7 +/- 2.3 (mean +/- SD) percent of the activity values for samples kept at +37 degrees C (n equals 63). In the routine setting, 6.25 pg of angiotensin l or 10(-6) Goldblatt units of Standard Human Renin was detected. We report results of plasma renin activity measurements and a comparison with seven renin kits, and with bioassay for plasma renin activity.
D000328:Adult; D000804:Angiotensin II; D001681:Biological Assay; D005069:Evaluation Studies as Topic; D005260:Female; D005498:Follicular Phase; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006929:Hyperaldosteronism / Q000097:blood; D006973:Hypertension / Q000097:blood; D007457:Iodine Radioisotopes; D007668:Kidney / Q000502:physiology; D008297:Male; D008875:Middle Aged; D011863:Radioimmunoassay / Q000379:methods; D012083:Renin / Q000097:blood*
D007457:Iodine Radioisotopes; D000804:Angiotensin II; D012083:Renin