Effect of Cortisone on the Peripheral Degradation of131I-Thyroxine

Abstract

The peripheral degradation of ¹³¹I-thyroxine during the administration of cortisone was studied in euthyroid persons. The administration was accompanied by a statistically significant increase in the radioactivity excreted in the urine due to an increase in the amount of free radioiodide in the urine. This indicates an increase in the peripheral degradation of thyroxine during the administration of cortisone. The slope of the radiothyroxine disappearance curve for blood was reduced during the administration of large doses of cortisone.