title: Radioimmunoassays of T3, r-T3 and r-T'2 in human serum.
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 princple 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 labelled hormone, an overnight incubation at room temperature and a separation of bound and free hormone with dextran-coated charcoal. The methods require 15 microliter, 50 microliter and 100 microliter (or 333 microliter for ethanol extraction) serum respectively. Serum concentrations (mean +/- SD) of T3, r-T3 and r-T'2 from normal subjects are 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).
mesh_terms: D004104:Diiodothyronines / Q000097:blood*; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood / Q000175:diagnosis; D007037:Hypothyroidism / Q000097:blood / Q000175:diagnosis; D011863:Radioimmunoassay / Q000379:methods*; D012016:Reference Values; D013970:Thyronines / Q000097:blood*; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood*; D014285:Triiodothyronine, Reverse / Q000097:blood*
chemical_list: D004104:Diiodothyronines; D013970:Thyronines; D014284:Triiodothyronine; D014285:Triiodothyronine, Reverse; D013974:Thyroxine