Radioimmunoassays of T3, r‐T3 and r‐T2 in Human Serum

Publisher Website
Google Scholar
Abstract
Simple radioimmunoassays for 3,3'',5-triiodothyronine (T3), 3,3'',5''-reverse-triiodothyronine (r-T3) and 3,3''-diiodothyronine (r-T''2) in human serum are described. The principle of the methods is the same and based on a system using 8-anilino-1-naphthalene sulfonic acid as an inhibitor of nonspecific protein binding, a simultaneous addition of the antibody and the labeled hormone, an overnight incubation at room temperature and a separation of bound and free hormone with dextran-coated charcoal. The methods require 15 .mu.l, 50 .mu.l and 100 .mu.l (or 333 .mu.l for ethanol extraction) serum, respectively. Serum concentrations (mean .+-. SD) of T3, r-T3 and r-T''2 from normal subjects were 144 .+-. 19 ng T3/100 ml (n = 52), 32 .+-. 7 ng r-T3/100 ml (n = 36), 3.8 .+-. 0.7 ng r-T''2/100 ml (ethanol extraction, n = 18) and 8.2 .+-. 1.6 ng r-T''2/100 ml (unextracted, n = 16).