title: Urinary triiodothyronine excretion.
abstract: The purpose of this work was to estimate the 24 h urinary excretion of free and conjugated triiodotironine (T3) using a direct radioimmunoassay and enzyme hydrolysis. Mean urinary values of free and total T3 (mean +/- 1 SD) in euthyroid controls were 2074 +/- 673 and 2819 +/- 809 pmol/24 h respectively. In patients with hyperthyroidism, values of free hormone were about 4.2 times higher than the mean value of the euthyroid controls, and about one-third in patients with hypothyroidism. These results show this measurement to be useful as an indicator of thyroid function. Mean renal clearance of free T3 was 211.6 +/- 62.8 ml/min (mean +/- 1 SD) in euthyroid controls, 260.8 +/- 87.5 ml/ml in hyperthyroid patients and 229 +/- 98.7 ml/min in hypothyroid patients. The data show that T3 renal clearance is, in all cases, greater than glomerular filtration rate, suggesting tubular secretion of T3.
authors.affiliation: Departamento de Fisiología, Facultad de Medicina y Hospital Clínico Universitario, Zaragoza, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Orden
authors.forename: J
authors.initials: J
authors.lastname: Pié
authors.forename: M G
authors.initials: MG
authors.lastname: Juste
authors.forename: A
authors.initials: A
authors.lastname: Giner
authors.forename: M E
authors.initials: ME
authors.lastname: Gómez
authors.forename: J F
authors.initials: JF
authors.lastname: Escanero
mesh_terms: D000328:Adult; D000368:Aged; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood / Q000652:urine*; D007037:Hypothyroidism / Q000097:blood / Q000652:urine*; D007668:Kidney / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D014284:Triiodothyronine / Q000097:blood / Q000652:urine*
chemical_list: D014284:Triiodothyronine