title: Old and new fields of research on the tryptophan.
mesh_terms: D000818:Animals; D007736:Kynurenic Acid / Q000378:metabolism; D051381:Rats; D014364:Tryptophan / Q000378:metabolism*; D014977:Xanthurenates / Q000378:metabolism
chemical_list: D014977:Xanthurenates; D014364:Tryptophan; D007736:Kynurenic Acid