The inducibility of aryl hydrocarbon hydroxylase (AHH) in mouse hepatoma Hepa-1 cell culture has been used as a quantitative bioassay for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The detection limit was 0.5pM TCDD. The basal AHH activity was about 2U/mg protein, and the maximally induced activity was about 100U/mg protein. ED50 for TCDD was 7pM. Similar data were obtained using 7-ethoxyresorufin as a substrate (EROD activity). Extraction of several consumer paper products with acetone gave an uncharacterised mixture of AHH inducers. The estimated TCDD (equivalents) in these extracts varied between 0 and 42pg/g of paper.
KarenlampiS.O., TuomiK., KorkalainenM., and RaunioH. (1989a). Induction of cytochrome P450-IA1 in mouse hepatoma cells by several chemicals. Phenobarbital and TCDD induce the same form of cytochrome P450.Biochemical Pharmacology38, 1517–1525.
2.
KärenlampiS.O., TuomiK., KorkalainenM., and RaunioH. (1989b). 2-(4′–chlorophenyl)benzothiazole, a potent inducer of cytochrome P450IA1 in a human and a mouse cell line. Anomalous correlation between protein and mRNA induction.European Journal of Biochemistry181, 143–148.
3.
NebertD.W. (1988). Genes encoding drug-metabolizing enzymes: possible role in human disease. In Phenotypic Variation in Populations: Relevance to Risk Assessment (ed. WoodheadA.D., BenderM.A., LeonardR.C.), pp. 45–64. New York: Plenum Press.
4.
NebertD.W., and GelboinH.V. (1968). Substrate-inducible microsomal aryl hydroxylase in mammalian cell culture. I. Assay and properties of induced enzyme.Journal of Biological Chemistry243, 6242–6249.
5.
BurkeM.D., and MayerR.T. (1974). Ethoxyresorufin: direct fluorimetric assay of a microsomal O-dealkylation which is preferentially inducible by 3-methylcholanthrene.Drug Metabolism and Disposition2, 583–588.
6.
BradlawJ.A., and CasterlineJ.L.Jr. (1979). Induction of enzyme activity in cell culture: A rapid screen for detection of planar polychlorinated organic compounds.Journal of the Association of Official Analytical Chemists62, 904–916.
7.
HankinsonO. (1983). Dominant and recessive aryl hydrocarbon hydroxylase-deficient mutants of mouse hepatoma line, Hepa-1, and assignment of recessive mutants to three complementation groups.Somatic and Cell Genetics9, 497–514.
8.
KärenlampiS.O., LegraverendC., GudasJ.M., CarramanzanaN., and HankinsonO. (1988). A third genetic locus affecting the Ah (dioxin) receptor.Journal of Biological Chemistry263, 10111–10117.
9.
KarenlampiS.O. (1987). Mechanism of cytotoxicity of Alflatoxin B1: Role of cytochrome P1-450.Biochemical and Biophysical Research Communications145, 854–860.
