Effect of Whole-Body X-Irradiation on Thyroid Function in the Mouse

The effect of whole-body X-irradiation with an exposure of 1000 R on thyroid function in mice was studied. The rate of thyroid¹³¹ I uptake in the irradiated animals was lower than that in the controls on the second day postirradiation. The radiochromatographic study of thyroid tissue hydrolyzates showed gradual suppression of thyroid hormone synthesis after irradiation. The initial 6-hour conversion ratio of plasma¹³¹ I was lower in the irradiated animals than in the controls. There was a temporary retardation in the thyroid hormone secretion after irradiation. From these experiments, with the additional support from the previous literature, it was concluded that a whole-body exposure of mice with 1000 R of X-rays acted as a stressor to reduce the various aspects of thyroid function during 6 to 48 hours after the exposure.