STUDIES ON THE THYROID ACTIVATOR OF HYPERTHYROIDISM*

Abstract

The thyroid activator of hyperthyroidism was distinguished from thyrotropin by its prolonged action in an assay for thyrotropin. It was sought in the serum of 10.1. persons and was found in: (a) 8 of 9 persons with exophthalmos and hyperthyroidism; (b) 19 of 25 persons without exophthalmos but with hyperthyroidism; (c) 19 of 23 persons with hyperthyroidism in the past but with persisting exophthalmos; (d) 11 of 14 persons with exophthalmos who had never had hyperthyroidism; and (e) only 1 of 25 persons with no history of either exophthalmos or hyperthyroidism. Included in these observations were 4 positive results on the serum of patients who had features of hypopituitarism due to pituitary-ablative surgery. Qualitative differences between thyrotropin and the thyroid activator of hyperthyroidism were found in: 1) serum fractionation studies by means of starch-block electrophoresis, chromatography on a column of diethylaminoethyl cellulose, and determinations by the percolation method of Bates; and 2) “half-life” experiments in mice, wherein the thyroid activator remained in the blood for several hours after injection, in contradistinction to the very short “half-life” of thyrotropin. It is suggested that the thyroid activator is of pathogenetic significance in Graves) disease and that it may be an entity distinct from pituitary thyrotropin.