The Effect of Vitamins A and C on Experimental Hyperthyroidism

Abstract

The basal metabolism and liver, kidney and thyroid tissue respirations of rats were studied to determine whether vitamin A and ascorbic acid could be shown to affect thyrotoxic tissue respiration as they do thyrotoxic basal metabolism. The effect of the vitamins alone was also studied. Vitamin A and ascorbic acid did reduce the hypermetabolism associated with hyperthyroidism to some extent. Only in one group of rats, the 18-month-old females, did vitamin A raise the metabolism slightly. In the other groups neither vitamin produced any alteration of normal basal heat production. Both ascorbic acid and vitamin A increased the respiratory rates of liver and of kidney cortical tissue. Ascorbic acid increased thyroid tissue respiration, while vitamin A depressed it. Increased liver and kidney tissue metabolism associated with hyperthyroidism was not altered by vitamins A or C. The depressed thyroid respiration, as a result of thyroxin administration, was not alleviated either by vitamin A or ascorbic acid. In fact, there were instances where the effect was additive, i.e., of the hormone plus the vitamin.