Fig. 3From: Aryl hydrocarbon receptor activation mediates kidney disease and renal cell carcinomaBiosynthesis of AhR ligands from tryptophan metabolism. Tryptophan is metabolized into various AhR ligands. a In the gastrointestinal tract, various bacterial species in the microbiota can metabolize tryptophan to products with AhR agonistic effects. b Cruciferous vegetables produce the tryptophan metabolite glucosinolate via a hydrolysis reaction, yielding the AhR protoagonist I3C. In the stomach, I3C is metabolized by an acid-condensation reaction to AhR ligands 6-formylindolo(3,2-b)carbazole (FICZ), DIM and LTr1. c Host metabolites such as IS and IAA, with AhR agonistic effect, are primarily derived from tryptophan metabolism through the kynurenine pathway, with other ligands generated by ultraviolet exposure and oxidative reactions. B1: indole-3-acetaldehyde; B2: S-(indolylmethylthiohydroximoyl) l-cysteine; B3: indolylmethyl thiohydroximate; TPH: tryptophan hydroxylaseBack to article page