Abstract
For 7 months 250 rats were fed on a specific synthetic diet, varied: (1) low Ca[long dash]low I, (2) high Ca[long dash]low I, (3) high Ca[long dash]adequate I. Continuous low I diet caused manifestations of exophthalmic goiter affecting activity, weight, reproduction, etc. Association between Ca and I metabolism was indicated by greater thyroid enlargement, degenerative changes in parathyroid, and decreased percentage of bone ash and Ca content of fat-free bones in cases in which Ca was added to I-deficient diets; greater decrease in blood I level in rats receiving additional Ca in diets of similar I content; and an inverse relationship in degree of cellular change of thyroid and parathyroid of rats on I-deficient diets with or without additional Ca.