title: Assay of angiotensin I by fluorescence polarization method.
abstract: Fluorescence polarization technique was applied for the assay of angiotensin I (Al) in human plasma. In this assay system, fluorescein labeled Al (F-Al), which retained the original antigenicity, and antibody to Al was allowed to interact in a cuvette in the instruments yielding an increase in the fluorescence polarization (P) value. Non-labeled Al in the sample blocked the binding of F-Al to the antibody resulting lower P value. Log of antigen concentration and P value was found to exhibit reverse linear proportionality between 0.05 ng to 2 ng/ml of antigen (Al) concentration. The present method was compared with standard radioimmunoassay method and the result showed that data were compatible with each other. The calculation of P value is automated and three cavity filter and optics of the instrument gave reliable results. The method is fast (less than 2 min), sensitive (less than 10 picomole/ml) and simple (no separation step before readout of the results).
mesh_terms: D000803:Angiotensin I / Q000097:blood*; D000809:Angiotensins / Q000097:blood*; D004306:Dose-Response Relationship, Immunologic; D005452:Fluoresceins; D006801:Humans; D012083:Renin / Q000097:blood; D013050:Spectrometry, Fluorescence / Q000295:instrumentation / Q000379:methods
chemical_list: D000809:Angiotensins; D005452:Fluoresceins; D000803:Angiotensin I; D012083:Renin