title: Thyroxine (T4) and triiodothyronine (T3) metabolism in normal subjects from Rio de Janeiro, Brazil.
abstract: Kinetic studies of T4 and T3 metabolism were performed on 5 healthy volunteers from Rio de Janeiro to obtain normal values for thyroid hormone metabolism. 125I-T4 and 131I-T3 were administered in bolus and blood samples taken during 7 days. Circulating tracers were isolated by Sephadex G-25 chromatography. The kinetic parameters of T4 and T3 metabolism were calculated by noncompartmental methods. Metabolic clearance rates were 1.04 l/day for T4 and 20.7 l/day for T3. The daily production rate was estimated at 94 micrograms/day for T4 and 23 micrograms/day for T3 and their exchangeable pools at 914 micrograms and 25.5 micrograms, respectively. These values are well within the range of those reported by North American or European authors for normal subjects.
authors.affiliation: Laboratório de Fisiologia Endócrina, Universidade Federal do Rio de Janeiro, Brasil.
authors.forename: B A
authors.initials: BA
authors.lastname: Cardoso
authors.forename: D
authors.initials: D
authors.lastname: Rosenthal
mesh_terms: D000328:Adult; D000368:Aged; D001938:Brazil; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D013974:Thyroxine / Q000378:metabolism*; D014284:Triiodothyronine / Q000378:metabolism*
chemical_list: D007457:Iodine Radioisotopes; D014284:Triiodothyronine; D013974:Thyroxine