[Relation of TRH test to thyroidal suppression test by triiodothyronine in patients with hyperthyroidism under treatment with antithyroid drugs (author's transl)].
The relation of the TRH test to the T3 suppression test was investigated in 43 patients with hyperthyroidism receiving antithyroid drugs for 6 to 27 months (average 14 months). TRH tests were performed by measuring serum TSH levels before and 15, 30, 45, 60, 90 and 120 minutes after intravenous injection of 500 mug of synthetic TRH. Serum TSH was measured by a double antibody radioimmunoassay. Two weeks later, the T3 suppression test was performed by measuring the 24-hr thyroidal uptake of radioiodine after daily administrations of 75 mug of triiodothyronine for 8 days. All patients under study were in euthyroid state, estimated by serum T3-RSU, T4, T3 and FT4I. The value for 24-h uptake after T3 administration was less than 20% in 18 cases, out of which the response to TRH was normal or exaggerated in 15 cases and was absent or impaired in 3 cases. On the other hand, out of 25 cases with the value of 24-h uptake more than 20%, the response to TRH was absent or impaired in 18 cases and was normal or exaggerated in 7 cases. The results of the TRH test and the T3 suppression test were correlated in 33 out of 43 cases. The responsiveness to TRH and the suppressibility with T3 was dissociated in 10 cases, suggesting the TRH test could not replace the T3 suppression test.
D000293:Adolescent; D000328:Adult; D000368:Aged; D013956:Antithyroid Agents / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology; D007457:Iodine Radioisotopes; D008297:Male; D008875:Middle Aged; D013960:Thyroid Function Tests; D013972:Thyrotropin / Q000378:metabolism; D013973:Thyrotropin-Releasing Hormone; D013997:Time Factors; D014284:Triiodothyronine
D013956:Antithyroid Agents; D007457:Iodine Radioisotopes; D014284:Triiodothyronine; D013973:Thyrotropin-Releasing Hormone; D013972:Thyrotropin