THE METABOLISM OF RATS AFTER THYROIDECTOMY OR DURING THIOURACIL TREATMENT,AND THEEFFECT OF THYROID FEEDING

Abstract
Rats placed on continual treatment with thiouracil given in the diet and drinking water show a slower decline in metabolic and heart rates than do thyroidectomized rats. This is probably due to the presence of stored thyroid hormone in the gland. The final metabolic rates in the thiouracil rats, however, reach athyroid levels. The drug is effective also in animals which, due to accessory thyroid tissue, show no reduced B.M.R. after thyroidectomy. The individual variations in the thiouracil treated rats are considerably larger than in the thyroidectomized animals, and their responses to ingestion of standard doses of thyroid are rather erratic and irregular.