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PubMed · 8005379

A toxic equivalency factor scale for polychlorinated dibenzofurans.

M Tysklind·D Tillitt·L Eriksson·K Lundgren·C Rappe
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Abstract

The ethoxyresorufin O-deethylase (EROD) induction of 20 polychlorinated dibenzofurans (PCDFs) was examined in the H4IIE rat hepatoma cell bioassay. The selection of the compounds tested was based on a multivariate chemical characterization laying the groundwork for covering the whole chemical series of PCDFs. The EROD induction potency was found to vary in ED50 values from 25 to 100,000,000 pg/mg, i.e., nearly seven orders of magnitude. The response of the bioassay was calibrated against the 2,3,7,8-tetrachlorodibenzo-p-dioxin, enabling the corresponding toxic equivalency factors (TEFs) to be calculated. In order to establish a quantitative structure-activity relationship (QSAR) for the TEF values, 37 physicochemical descriptor variables were used to chemically characterize the 87 tetra- to octachlorinated PCDFs. Using partial least-squares modeling on a training set of 10 congeners, a QSAR model with sound predictive power was obtained. The QSAR model was validated with a validation set of additional 10 congeners. The predicted TEFs indicate that a large number of congeners are potent EROD inducers.

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AnimalsBenzofuransChemical PhenomenaChemistry, PhysicalCytochrome P-450 CYP1A1Cytochrome P-450 Enzyme SystemDibenzofurans, PolychlorinatedEnzyme InductionFluorescenceLiver Neoplasms, ExperimentalOxidoreductasesPolychlorinated DibenzodioxinsRatsStructure-Activity RelationshipTumor Cells, CulturedJournal ArticleResearch Support, Non-U.S. Gov't

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M Tysklind, D Tillitt, L Eriksson, K Lundgren, C Rappe. 1994. A toxic equivalency factor scale for polychlorinated dibenzofurans.. https://doi.org/10.1006/faat.1994.1031

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