[TRH refractory TSH values, triiodothyronine levels and T3/T4 quotients in hypothyroid children treated with T3/T4 preparations (author's transl)].

TRH-tests, triiodothyronine (T3), TBI, and thyroxine (T4) determinations were carried out in 23 children with primary hypothyroidism treated with T3/T4-preparations. T3/T4 quotients were calculated. 7 out of 10 patients with TRH refractory TSH values and normal T4 levels had T3 values above normal range. In 6 of them pathologically elevated T3/T4 quotients could be observed. A TSH refractory TSH suppression was only found in patients with superior normal T4 values. After a reduction of the replacement doses the T3 values were normal. The findings show--that not only the T4 values should be controlled under treatment with thyroid preparations but also the T3 and TSH serum levels. The replacement therapy of hypothyroidism with T3/T4 preparations in proportion 1:4 should be revised.