THE RADIOIMMUNOASSAY OF 3,3‘,5’-TRHODOTHYRONINE (REVERSE T3) IN UNEXTRACTED HUMAN SERUM

摘要: Summary A specific, sensitive and simple double antibody radioimmunoassay for total serum 3,3′,5′,-triiodothyronine (reverse T3, rT3) in small volumes of unextracted human is described. High titre antisera were raised rabbits using dl-rt3 or l-rT3 conjugated to bovine albumin. The selected cross reacted less than 0–003% with triiodothyronine (T3) 0–14% thyroxine (T4). A stable high activity rT3 tracer was prepared by iodination 3,3′-diiodo-l-thyronine the chloramine-T method, purified column chromatography on Sephadex LH-20. Binding endogenous proteins blocked including 8-anilino-l-naphthalene sulphonic acid (ANS) assay. Mean levels healthy euthyroid adults are 0.27 nmol/1 (range 015–0.42); patients 0.29 0.11–0.80); thyrotoxic subjects 1.26 0.41–4.66); T3 0.47 0.21–1.18); cord sera 3.67 2.30–7.45) amniotic fluid taken during second trimester 4.70 2.22–8.00). In approximately half hypothyroid subjects, undetectable (<0.05 nmol/1) remaining mean level 0.10 0.05–0.25).