INFLUENCE OF CHOLESTYRAMINE ON ABSORPTION AND EXCRETION OF THYROXINE IN SYRIAN HAMSTER

Abstract

ABSTRACT Syrian hamsters were treated for one month with a diet containing 5 mg/100 g 1-thyroxine. If after this treatment with thyroxine the hamsters were fed a thyroxine-free diet with cholestyramine for one month, the thyroid glands were normal while in the controls they still had a »resting« appearance. In a second experiment hamsters were given a diet containing 131I 1-thyroxine with and without cholestyramine. A significantly smaller fraction of the radioactivity was found in the carcass, exclusive of the gastrointestinal tract, of the cholestyramine treated animals than in that of the controls. In a third experiment hamsters were injected intravenously with 131I 1-thyroxine and given diets with and without cholestyramine. The radioactivity of the cholestyramine treated animals was found to decrease more rapidly than that of the controls due to a larger excretion of radioactive material in the faeces. It is concluded that cholestyramine diminishes the absorption and promotes the excretion in the faeces of thyroxine or its iodine containing derivates.