Radioimmunoassay of human plasma α-ANP

Atrial natriuretic peptide（ANP）has been isolated from human atrium,It is a 28-amino acid residue peptide（MW=3081）.The phy siological function and importance of this peptide rests on its definite natriuretic and diuretic actions on the kidney as well as its vasodilatory effect in the regulation of blood pressure and body fluids.Radioimmunoassay of human plasma ANP was presented.Rabbit was immunized by α-ANP coupled with thyroglobulin（TG）.A specific antiserum was obtained and finely diluted to 1:3000,125 I-labled ANP was prepared by choramine-T method, its specific acivity being about 4.8 MBg/μg.Dextran-coated charcoal（Dcc）was used as the separating reagent.The sensitivty of the method was 10 pg.Assay range was 0.01-3.0 ng/tube.
The RIA method was simple,precise and sensitive.
Plasma ANP values of 22 health adults have been detemined by ANP-RIA and their range was from 100-880 pg/ml.The ANP concentration of rabbit and guinea-pig atrium was found to be 4.85 nmol/g and 4.74 nmol/g respectively.