title: Identification of the Ah receptor in selected mammalian species and induction of aryl hydrocarbon hydroxylase.
abstract: The Ah receptor protein, important in the mechanism of induction of aryl hydrocarbon hydroxylase activity, has been identified and partially characterized in hepatic cytosolic preparations from rat, BALB/c mouse, gerbil, hamster, rabbit, ferret and guinea-pig by means of sucrose density centrifugation analysis and hydroxyapatite binding assays. Using 2,3,7,8-tetrachloro[3H]dibenzo-p-dioxin (TCDD) as the ligand, total specific binding capacities ranged over 74-691 fmol [3H]TCDD/mg cytosolic protein and apparent dissociation constants ranged over 0.30-7.8 nM. There was no quantitative correlation between the concentration of cytosolic Ah receptors and the 3-methylcholanthrene-mediated induction of aryl hydrocarbon hydroxylase activity in the species studied. Competitive binding studies with a series of monohydroxylated benzo[a]pyrene derivatives suggested the importance of electronic character in their ability to bind to the Ah receptor and to compete with TCDD for specific binding sites on the receptor.
authors.forename: M S
authors.initials: MS
authors.lastname: Denison
authors.forename: C F
authors.initials: CF
authors.lastname: Wilkinson
mesh_terms: D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000096:biosynthesis*; D001667:Binding, Competitive; D002499:Centrifugation, Density Gradient; D055598:Chemical Phenomena; D002621:Chemistry; D006224:Cricetinae; D003600:Cytosol / Q000201:enzymology; D004790:Enzyme Induction / Q000187:drug effects; D005289:Ferrets; D005849:Gerbillinae; D006168:Guinea Pigs; D008297:Male; D008748:Methylcholanthrene / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D008862:Microsomes, Liver / Q000201:enzymology; D000072317:Polychlorinated Dibenzodioxins / Q000378:metabolism; D011817:Rabbits; D051381:Rats; D011919:Rats, Inbred Strains; D018336:Receptors, Aryl Hydrocarbon; D011955:Receptors, Drug / Q000032:analysis*; D013045:Species Specificity
chemical_list: D000072317:Polychlorinated Dibenzodioxins; D018336:Receptors, Aryl Hydrocarbon; D011955:Receptors, Drug; D008748:Methylcholanthrene; D001189:Aryl Hydrocarbon Hydroxylases