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pubmed:abstractText |
The effect of exposure time on the induction of 7-ethoxyresorufin O-deethylase (EROD) by 2,3,7,8,-tetrachlorodibenzo-p-dioxin (TCDD), 2,3,7,8-tetrachlorodibenzofuran (TCDF), and 3,3',4, 4'-tetrachlorobiphenyl (PCB 77) was examined in two liver cell lines: rainbow trout RTL-W1 and rat H4IIE. In RTL-W1, exposure time had no effect on induction EC50s and derivation of TCDD- toxic equivalency factors (TEFs). In H4IIE, EC50s for TCDD also were unchanged. However, for TCDF and PCB 77 in H4IIE, EC50s increased and TEFs decreased as exposure time increased from 6 to 72 h. These results suggest that metabolism of TCDF and PCB 77 can account for some of the previously observed differences between RTL-W1 and H4IIE TEFs.
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pubmed:articleTitle |
Derivation of 2,3,7,8-TCDD toxic equivalent factors (TEFs) for selected dioxins, furans and PCBs with rainbow trout and rat liver cell lines and the influence of exposure time.
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