Effects of tabolism inPeroxidation Products of Rats LinoleicAcid on Tryptophan - nicotinamideMe -

The flayin and pyridine nucleotide coenzymes are inyolved in the detoxication f ftutoxidation produets of lipids. In tryptophan-nicotinamide metabolism, kynurenine 3-hydroxylase and IVi-methylnicotinamide (MNA) oxidase contain FAD as a coenzyme. So, the effects of dietary autoxidation products of linoleic acid on the metabolism of tryptophan-nicotinamide were inyestigated using rats. The administration of linoleic a id hydroperoxides or secondary products reduced the urinary excretion of xanthurenic acid, nicotinamide and its metabolites su ¢h as MNA, Ni-methyl-2-pyridone-5-carboxamide (2-Py), and IVi-methyl-4-pyridone-3-carboxamide (4-Py) as compared with the group administered saline or linoleic acid. Among the enzyme activit;es inyolyed in the tryptophan-nicotinamide metabolism, the activity of NAD" synthetase was decreased by the administration of Iinoleic acid hydroperoxides or secondary products. The actiyities of tryptophan oxygenase aRd 4-Py-forming MNA oxidase were also decreased by the administration of secondary products. These results indicate that the conversion of tryptophan to nicetinamide would be lower in the groups administered the hydroperoxides and secondary products than in saline and linoleic acid groups.