THYROGLOBULIN IN SERUM AFTER TSH STIMULATION IN HYPERTHYROIDISM

ABSTRACT Thyroglobulin in serum was demonstrated by a haemagglutination-inhibition technique and a reversed haemagglutination technique. Circulating thyroglobulin was found in 12 of 15 hyperthyroid patients – both before and during treatment with methylthiouracil – but in none of 12 euthyroid subjects. In three hyperthyroid patients it was not possible to determine thyroglobulin, as thyroglobulin antibody was present in the serum. After TSH stimulation thyroglobulin appeared in the serum of nine of the 12 euthyroid subjects and the thyroglobulin level increased in five of the 12 untreated and six of the 12 treated hyperthyroid patients. The serum thyroxine, T3 uptake in resin and 131I uptake in the thyroid gland at 4 and 24 h were increased after TSH stimulation in all the euthyroid cases; the hyperthyroid patients (both before and during treatment), however, only showed a slight but significant increase in serum thyroxine and 4 h 131I uptake, while the T3 uptake in resin and the 24 h 131I uptake did not rise at all. LATS was found in serum of only five of 15 untreated hyperthyroid patients. No significant changes in the LATS content could be detected during treatment. The increased content of thyroglobulin in the serum of hyperthyroid patients seems to be due neither to greater sensitivity to TSH nor to the influence of LATS.