Assay of plasma renin activity using commercially available reagents

1.The rate of generation of Angiotensin 1 by plasma samples at 37° is a measure of their plasma renin activity. The generated Angiotensin 1 has been measured by radio-immunoassay using commercially available 125I-Angiotensin 1 and anti-Angiotensin 1 antiserum.2.Both the generation and radio-immunoassay phases of the procedure have been studied and alterations to the manufacturer's recommended protocol have been found necessary.3.Failure to control the pH of the generation phase of the assay results in a deviation from zero order kinetics.4.Use of damaged labelled peptide in the radio-immunoassay system results in a loss of sensitivity of the assay.5.Results are presented from normal subjects and patients with a variety of clinical conditions.