Efficiency of Exogenous Quinolinic Acid, A Metabolite of Tryptophan, as a Niacin Precursor in Rats

It is generally known that protein nutrition, especially tryptophan metabolites, niacin intake and amino acid balance are important for the prevention of pellagra. The pathway from tryptophan to NAD via kynurenine, 3-hydroxyanthranilic acid and quinolinic acid (QA) has been shown to be particularly important from the nutritional standpoint (Krehl et al., 1946; Henderson and Hirsch, 1949; Nishizuka and Hayaishi, 1963).