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MEASUREMENT OF SERUM 3,3‘,5’‐(REVERSE) T3, WITH COMMENTS ON ITS DERIVATION
Author(s) -
GRIFFITHS R. S.,
BLACK E. G.,
HOFFENBERG R.
Publication year - 1976
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/j.1365-2265.1976.tb03871.x
Subject(s) - reverse triiodothyronine , serial dilution , radioimmunoassay , medicine , endocrinology , triiodothyronine , antiserum , serum concentration , chemistry , hormone , immunology , antibody , pathology , alternative medicine
Summary A radioimmunoassay for the measurement of l ‐3,3′,5′‐triiodothyronine (reverse T3, rT3) has been developed for use with unextracted serum. The highly specific antiserum showed no cross‐reactivity with l ‐3,3'5‐triiodothyronine (T3) or tetraiodothyroacetic acid (T4A) and cross‐reaction with l ‐thyroxine (T4) was low enough to be discounted for routine assay purposes. If a normal amount of rT3 was added to serum T4 cross‐reactivity decreased considerably. Serial dilutions of hyperthyroid sera gave dose‐response curves which were parallel to the rT3 standard curve. Serum concentrations of rT3 (mean ± SEM) were 0.68 ± 0.02 nmol/1 in sixty‐seven normal subjects, 0.19 ± 0.02 nmol/1 in twelve hypothyroid patients and 1.18 ± 0.12 nmol/1 in seventeen hyperthyroid patients. In sixteen patients with T3‐toxicosis rT3 was 0.42 ± 0.04 nmol/1 and eighteen patients with high circulating TBG had a mean rT3 of 0.54 ± 003 nmol/1.