THYROID FUNCTION IN EUTHYROID SUBJECTS WITH AUTONOMOUS THYROID NODULES

Abstract

SUMMARY The biochemical abnormalities in euthyroid subjects with autonomous thyroid nodules have been defined. Seven subjects have been studied in detail. None were hyperthyroid and conventional tests of thyroid function were normal. The characteristic abnormalities were noted on scanning. The absent response to TRH demonstrated that pituitary TSH suppression was present in all subjects. A moderate elevation of serum triiodothyronine (T 3 ) concentration, 1.89‐3.07 ng/ml, was noted. It is concluded that autonomous nodules in the euthyroid subjects studied are associated with elevated T 3 levels sufficient to produce pituitary suppression but not high enough to be associated with the clinical manifestations of hyperthyroidism.