title: Indole and Tryptophan Metabolism: Endogenous and Dietary Routes to Ah Receptor Activation.
abstract: The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor recognized for its role in xenobiotic metabolism. The physiologic function of AHR has expanded to include roles in immune regulation, organogenesis, mucosal barrier function, and the cell cycle. These functions are likely dependent upon ligand-mediated activation of the receptor. High-affinity ligands of AHR have been classically defined as xenobiotics, such as polychlorinated biphenyls and dioxins. Identification of endogenous AHR ligands is key to understanding the physiologic functions of this enigmatic receptor. Metabolic pathways targeting the amino acid tryptophan and indole can lead to a myriad of metabolites, some of which are AHR ligands. Many of these ligands exhibit species selective preferential binding to AHR. The discovery of specific tryptophan metabolites as AHR ligands may provide insight concerning where AHR is activated in an organism, such as at the site of inflammation and within the intestinal tract.
authors.affiliation: Graduate Program in Biochemistry, Microbiology, and Molecular Biology (T.D.H.), and Center for Molecular Toxicology and Carcinogenesis and the Department of Veterinary and Biomedical Sciences (T.D.H., I.A.M., G.H.P)., Pennsylvania State University, University Park, Pennsylvania.
authors.forename: Troy D
authors.initials: TD
authors.lastname: Hubbard
authors.affiliation: Graduate Program in Biochemistry, Microbiology, and Molecular Biology (T.D.H.), and Center for Molecular Toxicology and Carcinogenesis and the Department of Veterinary and Biomedical Sciences (T.D.H., I.A.M., G.H.P)., Pennsylvania State University, University Park, Pennsylvania.
authors.forename: Iain A
authors.initials: IA
authors.lastname: Murray
authors.affiliation: Graduate Program in Biochemistry, Microbiology, and Molecular Biology (T.D.H.), and Center for Molecular Toxicology and Carcinogenesis and the Department of Veterinary and Biomedical Sciences (T.D.H., I.A.M., G.H.P)., Pennsylvania State University, University Park, Pennsylvania ghp2@psu.edu.
authors.forename: Gary H
authors.initials: GH
authors.lastname: Perdew
mesh_terms: D000818:Animals; D019587:Dietary Supplements; D005638:Fruit / Q000378:metabolism; D041981:Gastrointestinal Tract / Q000378:metabolism; D006801:Humans; D007211:Indoles / Q000378:metabolism*; D018336:Receptors, Aryl Hydrocarbon / Q000378:metabolism*; D014364:Tryptophan / Q000378:metabolism*; D014675:Vegetables / Q000378:metabolism
chemical_list: D007211:Indoles; D018336:Receptors, Aryl Hydrocarbon; C030374:indole; D014364:Tryptophan