1998 Volume 72 Issue 10 Pages 515-522
The nutritional efficiencies of the intermediates of the tryptophan-niacin pathway and the related compounds of nicotinic acid and nicotinamide as a substitute for nicotinic acid were investigated using weanling rats fed the niacin-deficient diet. Judging from the growth response, levels of liver NAD, blood NAD, and urinary excretion of nicotinamide and its metabolites, we have concluded that tryptophan, 3-hydroxyanthranilic acid, quinolinic acid, nicotinamide N-oxide, N'-methylnicotinamide, nicotinuric acid, 3-acetylpyridine, pyridine 3-aidehyde, pyridine 3-methanol, β-picoline, or nicotinic acid N-oxide is approximately 1/10, 1/12, 1/24, 1/5, 1/2, 1/10, 1/10, 1/1, 1/1, 1/10, or 1/2 active as nicotinic acid, however, that N-formylkynurenine, kynurenine, 3-hydroxykynurenine, anthranilic acid, cinchomeronic acid, 3-cyanopyridine, 6-hydroxynicotinic acid, and pyridine 3-sulfonic acid do not have any niacin activity. Only 6-aminonicotinamide of the examined compounds showed the very strong antagonistic activity against niacin.
