Nontoxic Diffuse Goiter Research Articles

The Effect of Suppressive Therapy of Nontoxic Diffuse Goiter on Serum Levels of Thyroxine, 3,5,3‘‐Triiodothyronine and 3,3’,5‘‐Triiodothyronine

We studied the effect of suppressive therapy with graded doses of thyroxine (T4) on serum levels of T4, 3,5,3'-triiodothyronine (T3) and 3,3',5'-triiodothyronine [rT3] in patients with diffuse, nontoxic goiter. For comparison and in order to elucidate the degree of suppression of the pituitary thyroid axis by T3 the effect of suppressive therapy with T3 was studied in the same type of patients. We found that T4 in serum rose significantly to a constant level during T4 treatment (0.10, 0.15 and 0.20 mg/day). Dose-related rises in T4 were only seen after 3 months of treatment. T3 and rT3 only changed minimally. The T4/T3 ratio rose to a constant level during the initial 3 months of treatment. T3/rT3 ratio remained unchanged. No dose-related differences in T4/T3 and T3/rT3 ratio were observed. Treatment with T3 in doses of 0.06 mg per day caused a significant but slow fall in T4 and rT3 to hypothroid levels while T3 only rose slightly. The T4/T3 ratio dropped significantly during T3 therapy.

The thiocyanate suppression test--a new and simple test for differential diagnosis between hyperthyrodism and nontoxic goiter.

The thiocyanate suppression test, as described in the present paper, has proved to be a useful diagnostic assay in patients in whom the thyroidal radioiodine uptake or the clinical findings are equivocal. Thiocyanate, administered during 2 days by mouth at a total dose of 3 g, caused a sharp decrease in the 24-hr I131 uptake in 9 euthyroid patients and in 28 subjects with nontoxic diffuse goiter or nontoxic nodular goiter. No value exceeded 20%. In contrast, no value under 20% was obtained in 17 patients with thyrotoxicosis following thiocyanate administration.