TRIIODOTHYRONINE LEVELS IN PATIENTS WITH EUTHYROID ENDOCRINE EXOPHTHALMOS AND DURING TREATMENT OF THYROTOXICOSIS

Abstract

ABSTRACT Serum triiodothyronine (T3) concentrations have been measured in 7 patients with euthyroid endocrine exophthalmos and in 8 patients with hyperthyroidism. These results have been assessed in relation to other tests of thyroid function. The non-suppressibility of euthyroid endocrine exophthalmos is due to elevated endogenous T3 levels and correlated to a negative response of the pituitary gland to TRH. In hyperthyroid patients who are euthyroid under antithyroid drug therapy, no general correlation of routine laboratory data with T3 levels, suppressibility and TRH response could be found. There is a gap between normal T3 and T4 levels and the restoration of the normal TRH response. A condition is described in which euthyroid patients show thyrotoxic behaviour of the pituitary receptors.