AHR and type 2 diabetes mellitus: Promoted microbial conversion of tryptophan (indoleacetic acid, indole-3-lactic acid, and indole-3-propionic acid) to AhR ligands in the fecal microbiota of patients with T2DM.Enhanced the abundance of Allobaculum, Lactobacillus, Akkermansia, and Prevotellaceae in the mice.Reduced intestinal inflammation.Increased concentrations of glycine-conjugated bile acids, DCA, and isoDCA, as well as acetate, propionate, and butyrate in mice.