Prevention and Remission by Adrenocortical Steroids of Nicotinamide Deficiency Disease

Liver NAD and NADH each decreased by 25 to 40% in animals fed a nicotinamide-deficient diet for 4 weeks. In contrast, the nicotinamide-deficient diet had a negligible effect on the amount of liver NADP and NADPH, suggesting a closer regulation by the body of the levels of the latter two compounds. Adrenal steroids prevented the depletion of NAD and NADH which otherwise occurred in rats fed the nicotinamide-deficient diet. Moreover, in animals in which liver NAD and NADH had been depleted by feeding the deficient diet, the levels of these coenzymes could be restored to normal, or above normal, by steroid administration. Administration of steroids also increased the amount of NADP and NADPH. Evidence is presented that the ability of the steroids to increase the levels of the pyridine nucleotides is mediated by increasing the availability of tryptophan. The present results provide an explanation for our previous observations that adrenocortical steroids are able to prevent nicotinamide deficiency disease and even cause its remission.