title: Characterization of a murine Ahr null allele: involvement of the Ah receptor in hepatic growth and development.
abstract: The Ah receptor (AHR) is a ligand-activated transcription factor that mediates a pleiotropic response to environmental contaminants such as benzo[a]pyrene and 2,3,7,8-tetrachlorodibenzo-p-dioxin. In an effort to gain insight into the physiological role of the AHR and to develop models useful in risk assessment, gene targeting was used to inactivate the murine Ahr gene by homologous recombination. Ahr-/- mice are viable and fertile but show a spectrum of hepatic defects that indicate a role for the AHR in normal liver growth and development. The Ahr-/- phenotype is most severe between 0-3 weeks of age and involves slowed early growth and hepatic defects, including reduced liver weight, transient microvesicular fatty metamorphosis, prolonged extramedullary hematopoiesis, and portal hypercellularity with thickening and fibrosis.
authors.affiliation: Department of Molecular Pharmacology, Northwestern University Medical School, Chicago, IL 60611, USA.
authors.forename: J V
authors.initials: JV
authors.lastname: Schmidt
authors.forename: G H
authors.initials: GH
authors.lastname: Su
authors.forename: J K
authors.initials: JK
authors.lastname: Reddy
authors.forename: M C
authors.initials: MC
authors.lastname: Simon
authors.forename: C A
authors.initials: CA
authors.lastname: Bradfield
mesh_terms: D000483:Alleles; D000818:Animals; D002460:Cell Line; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis; D005260:Female; D018390:Gene Targeting; D008099:Liver / Q000187:drug effects / Q000196:embryology* / Q000201:enzymology / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010641:Phenotype; D000072317:Polychlorinated Dibenzodioxins / Q000633:toxicity; D018336:Receptors, Aryl Hydrocarbon / Q000235:genetics / Q000502:physiology*
chemical_list: D000072317:Polychlorinated Dibenzodioxins; D018336:Receptors, Aryl Hydrocarbon; D003577:Cytochrome P-450 Enzyme System