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DETERMINATION OF 2,3,7,8-TCDD TOXIC EQUIVALENT FACTORS (TEFS): SUPPORT FOR THE USE OF THE IN VITRO AHH INDUCTION ASSAY
Citation:
Safe, S. DETERMINATION OF 2,3,7,8-TCDD TOXIC EQUIVALENT FACTORS (TEFS): SUPPORT FOR THE USE OF THE IN VITRO AHH INDUCTION ASSAY. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-87/527.
Description:
The in vitro induction of the cytochorm P1-450-dependent monooxygenases, aryl hydrocarbon hydroxylase (AHH) or ethoxyresorufin O-deethylase (EROD) by 2,3,7,8-TCDD and related toxic halogenated aryl hydrocarbons in rat hepatoma H-4-II E cells has been developed as a short term quantitative bioassay for these toxic chemicals. here was a linear correlation between the -log EC50 (in vitro) AHH induction vs the -log ED50 (in vivo) or body polychlorinated biphenyl, dibenzo-p-dioxin and dibenzofuran congeners and mixtures. hese data clearly support the utility of the in vitro AHH induction assay as a short term test system for quantitating the "toxic or 2,3,7,8-TCDD equivalents" in an extract containing toxic halogenated aromatics. he bioassay method is rapid, relatively accurate and much more cost effective than conventional analytical methods such as gas-chromatography-mass spectrometry from which it is difficult to determine the levels of 2,3,7,8-TCDD equivalents in specific analytes.