FURTHER EVIDENCE FOR A THYROID ACTIVATOR IN HYPERTHYROIDISM*

Abstract

In mice fed desiccated thyroid (u.s.p.) the intravenous injection of sera from patients with hyperthyroidism caused an increased thyroidal uptake of I¹³¹ if given twelve hours before injection of the radioisotope. This was distinct from the effect of standard thyrotropin which produced a maximal increase if injected four hours before the I¹³¹. Activation of the mouse thyroid gland by the injected sera was indicated also by an increase in the level of the protein-bound I¹²⁷ of the plasma and by histologic changes in the thyroid.