SEARCH Articles Figures Tables Formation of Kynurenic and Xanthurenic Acids Pregnancy, xanthurenic acid excretion Pyridoxine deficiency xanthurenic acid, excretion Tryptophan Xanthurenic acid Tryptophan-kynurenine-xanthurenic acid Tryptophan-kynurenine-xanthurenic acid pathway Xanthurenate Xanthurenic acid 8-methyl ether Xanthurenic acid biosynthesis Xanthurenic acid formation Xanthurenic acid from tryptophan metabolism Xanthurenic acid structure