title: On the regulation of tryptophan metabolism "via" kynurenine.
abstract: The tryptophan leads to nicotinic acid pathway is inhibited in the nicotinic acid administered rats; in this case tryptophan chiefly metabolizes "via" serotonin. The serotonin pathway is inhibited in the excess phenylalanine administered rats, especially due to the inhibition of the tryptophan-5-hydroxylase reaction. Xanthurenic acid inhibits kynurenine-3-hydroxylase in vitro, which is a very important regulatory enzyme for xanthurenic acid and nicotinic acid production.
mesh_terms: D000818:Animals; D006863:Hydrogen-Ion Concentration; D006897:Hydroxyindoleacetic Acid / Q000652:urine; D006900:Hydroxylation; D007737:Kynurenine / Q000378:metabolism* / Q000652:urine; D006899:Mixed Function Oxygenases / Q000302:isolation & purification / Q000502:physiology*; D009243:NAD / Q000502:physiology; D009249:NADP / Q000502:physiology; D009539:Nicotinic Acids / Q000494:pharmacology; D010649:Phenylalanine / Q000494:pharmacology; D051381:Rats; D012701:Serotonin / Q000378:metabolism; D012995:Solubility; D014364:Tryptophan / Q000378:metabolism*; D014977:Xanthurenates / Q000494:pharmacology / Q000652:urine; D062367:ortho-Aminobenzoates / Q000378:metabolism / Q000652:urine
chemical_list: D009539:Nicotinic Acids; D014977:Xanthurenates; D062367:ortho-Aminobenzoates; D009243:NAD; D012701:Serotonin; D007737:Kynurenine; D010649:Phenylalanine; D009249:NADP; D006897:Hydroxyindoleacetic Acid; D014364:Tryptophan; D006899:Mixed Function Oxygenases