NICOTINAMIDE ADENINE DINUCLEOTIDE LEVELS IN RAT BRAIN

Albino rats were fed diets which were deficient in tryptophan, niacin, or both, until severe deficiency symptoms appeared. The brains were analyzed for their content of oxidized and reduced nicotinamide adenine dinucleotides (NAD), which are derived from dietary tryptophan and niacin. Deficiencies of tryptophan or niacin had little or no effects on the levels of NAD in rat brain. The injection of niacinamide in massive doses caused a 50 to 75% increase in the NAD levels. Reserpine had no significant effect on brain NAD. No "tranquilizing" or depressing effects were noticed after niacinamide injection.