title: A highly specific radioreceptor assay for the active circulating form of atrial natriuretic factor in human plasma.
abstract: This highly sensitive radioreceptor assay (RRA) for the active circulating form of atrial natriuretic factor (ANF), fragment 99-126, in human plasma requires 125I-labeled ANF, bovine zona-glomerulosa membrane receptors, and amiloride HCl. The amiloride elicits an increase in the binding affinity of ANF to its receptors. ANF is extracted from human plasma with "Sep-Pak" cyano cartridges. After a 90-min incubation at 25 degrees C, bound and free fractions are separated by filtration. The ANF concentration that inhibits receptor binding of the radioligand by 50% is 12.4 fmol of unlabeled ANF per tube. The minimum detectable concentration is 0.2 fmol per tube. Using ANF-supplemented plasma samples, there was a good correlation (r = 0.99) between ANF concentrations found and those expected. Only the active circulating form of ANF fully cross-reacts in this assay, which confirms its high selectivity. Results correlated strongly (r = 0.93) for clinical samples tested by RRA and RIA.
authors.affiliation: Clinical Research Institute, Montreal, Quebec, Canada.
authors.forename: H
authors.initials: H
authors.lastname: Ong
authors.forename: A
authors.initials: A
authors.lastname: De Léan
authors.forename: C
authors.initials: C
authors.lastname: Gagnon
mesh_terms: D000302:Adrenal Cortex / Q000032:analysis; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000097:blood*; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D003429:Cross Reactions; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood; D008722:Methods; D010656:Phenylephrine / Q000627:therapeutic use; D011863:Radioimmunoassay; D011869:Radioligand Assay; D011933:Reagent Kits, Diagnostic; D017461:Receptors, Atrial Natriuretic Factor; D011956:Receptors, Cell Surface / Q000378:metabolism
chemical_list: C472955:NPPA protein, human; D011933:Reagent Kits, Diagnostic; D011956:Receptors, Cell Surface; D010656:Phenylephrine; D009320:Atrial Natriuretic Factor; D017461:Receptors, Atrial Natriuretic Factor