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

Abstract

Syrian hamsters were treated for one month with a diet containing 5 mg/100 g 1-thyroxine. If after treatment with thyroxine the hamsters were fed a thyroxine-free diet with cholestyramlne 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 I131 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 I1311-thyroxine and given diets with and without cholestyramine. The radioactivity of the cholestyramine treated animals decreased more rapidly than that of the controls due to a larger excretion of radioactive material in the faeces. Cholestyramine diminishes the absorption and promotes the excretion in the feces of thyroxine or its iodine containing derivates.