THE INFLUENCE OF DIETARY THYROID ON THE BONES AND PERIODONTIUM OF RATS ON TOTAL AND PARTIAL TRYPTOPHAN DEFICIENCIES

¹ Department of Biochemistry and Nutrition, School of Dentistry and Medicine, and Department of Anatomy, School of Medicine, University of Southern California, Los Angeles, Calif.

The effects of experimental hyperthyroidism were studied on the bones and dental structures of rats fed a tryptophan-deficient ration supplemented with graded levels of dl-tryptophan. Diets containing 600 mg. dl-tryptophan per kilogram of diet or less resulted in inhibition and retardation of both endochondral and periosteal bone formation. Marked osteoporosis was noted in the alveolar bone of the molar teeth.

These effects were accentuated by desiccated thyroid. At higher levels of tryptophan supplementation, the above findings were minimal in both control and thyroid-fed groups. Ulceration of gingival epithelium and crater formation occurred in rats fed a tryptophan-free ration supplemented with 600 mg. or less of tryptophan in animals receiving dietary thyroid. These findings were not observed in animals receiving identical rations in the absence of dietary thyroid.