[Radioimmunologic determination of triiodothyronine in essential obesity]

A new convenient, specific, precise radioimmunoassay for measurement of T3 has been studied. The assay, set up in presence of ANS (to inhibit aspecific binding of T3 with TBP) and of T3 free serum in Standard curves, allows to measure serum T3 ranging between 6.25 and 800 ng/100 ml. The mean recovery of unlabelled T3 was 103%. Serial dilutions of hyperthyroid sera and of euthyroid sera in T3 free serum yelded expected values. Then, the AA. have studied two groups of obese subjects under various conditions. The behaviour and some possible T3 production mechanism in those groups is finally discussed.