A EUTHYROID MAN WITHOUT THYROXINE BINDING GLOBULIN*

Abstract

In the course of a survey of men in industry, an apparently euthyroid man was found whose serum has no thyroxine binding capacity in vitro. He was well nourished, working, and without complaints. The PBI was 3.0 [mu]g%, presumably due to the lack of TBG, but the BMR was normal, -9%. The serum cholesterol was 308 mg %; total serum proteins 7.3 g %, with normal electrophoretic distribution. But the thymol turbidity was 2 units, and cephalin flocculation 2 plus. There was a history of hepatitis. The case suggests that thyroxine may be secreted from the thyroid independently of the circulating TBG, and reach the tissues in sufficient quantity to maintain normal metabolism, even when the TBG is not measurable.