The Ah phenotype. Survey of forty-eight rat strains and twenty inbred mouse strains.
Forty-four inbred and four randombred rat strains and 20 inbred mouse strains were examined for their Ah phenotype by determining the induction of liver microsomal aryl hydrocarbon (benzo[a]pyrene) hydroxylase activity (EC 1.14.14.1) by intraperitoneal treatment with either beta-naphthoflavone or 3-methylcholanthrene. All 48 rat strains were found to be Ah-responsive. The maximally induced hydroxylase specific activities of the ALB/Pit, MNR/Pit, MR/Pit, SHR/Pit, and Sprague-Dawley strains were of the same order of magnitude as the basal hydroxylase specific activities of the ACI/Pit, F344/Pit, OKA/Pit, and MNR/N strains. Six of the 20 mouse strains were Ah-nonresponsive (i.e. lacking the normal induction response and presumably lacking detectable amounts of the Ah receptor). The basal hydroxylase specific activities of the BDL/N, NFS/N, STAR/N, and ST/JN mouse strains were more than twice as high as the maximally induced hydroxylase specific activity of the CBA/HT strain.--To date, 24 Ah-nonresponsive mouse strains have been identified, out of a total of 68 known to have been characterized. The reasons for not finding a single Ah-nonresponsive inbred rat strain--as compared with about one Ah-nonresponsive inbred mouse strain found for every three examined--remain unknown.
D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics* / Q000378:metabolism; D004790:Enzyme Induction; D051379:Mice / Q000235:genetics / Q000502:physiology*; D008815:Mice, Inbred Strains / Q000502:physiology; D010641:Phenotype; D011083:Polycyclic Compounds / Q000378:metabolism; D051381:Rats / Q000235:genetics / Q000502:physiology*; D011919:Rats, Inbred Strains / Q000502:physiology
D011083:Polycyclic Compounds; D001189:Aryl Hydrocarbon Hydroxylases