Potency of mixtures of polychlorinated biphenyls as inducers of dioxin receptor-regulated CYP1A activity in rat hepatocytes and H4IIE cells

In vitro induction of CYP1A1-associated activities in human and rodent cell lines by commercial and tissue-extracted halogenated aromatic hydrocarbons

“…The greater sensitivity of H4IIE and the order of PCB congener potency relative to TCDD are consistent with the comparative toxic and biochemical potencies reported in the literature [1,2,5,7,20]. The differences in sensitivity and potency are also consistent with recently published results for the induction of EROD activity in H4IIE [30]. Interestingly, the H4IIE cells used in our study seem to be more sensitive to TCDD and less sensitive to PCBs than those used in the recently published study.…”

In vitro induction of CYP1A1-associated activities in human and rodent cell lines by commercial and tissue-extracted halogenated aromatic hydrocarbons

“…The greater sensitivity of H4IIE and the order of PCB congener potency relative to TCDD are consistent with the comparative toxic and biochemical potencies reported in the literature [1,2,5,7,20]. The differences in sensitivity and potency are also consistent with recently published results for the induction of EROD activity in H4IIE [30]. Interestingly, the H4IIE cells used in our study seem to be more sensitive to TCDD and less sensitive to PCBs than those used in the recently published study.…”

Carcinogenic risks of dioxin: Mechanistic considerations

“…Importantly, the results obtained in these studies varied between exposure scenarios where only dioxin-like agents were combined and scenarios where mixtures between dioxin-like and non-dioxin-like chemicals were used. A perfect additive behavior in induction of CYP1A (EROD) activity was observed when using a mixture of potent dioxin-like PCBs, both in hepatocytes and in hepatoma cells in vitro (Schmitz et al, 1995). This result is in good agreement with earlier Wndings of the group using the same end-point but a mixture of diVerent dioxin congeners (Schrenk et al, 1991).…”

Dioxinlike Components in Incinerator Fly Ash: A Comparison between Chemical Analysis Data and Results from a Cell Culture Bioassay

“…The concept of I-TEFs is based on the assumption that the dioxinlike effects of the individual congeners are additive. Moreover, EROD-TEF values of PCDDs (19) and PCBs (21) in the bioassay were in very good agreement with I-TEFs and WHO-TEFs, respectively. However, the fact that most if not all toxic effects of TCDD and related compounds are mediated by a common receptor, the dioxin or aryl hydrocarbon receptor (AhR), is in favor of the concept of additivity (5,7,13).…”

In vitro induction of CYP1A1-associated activities in human and rodent cell lines by commercial and tissue-extracted halogenated aromatic hydrocarbons

“…The greater sensitivity of H4IIE and the order of PCB congener potency relative to TCDD are consistent with the comparative toxic and biochemical potencies reported in the literature [1,2,5,7,20]. The differences in sensitivity and potency are also consistent with recently published results for the induction of EROD activity in H4IIE [30]. Interestingly, the H4IIE cells used in our study seem to be more sensitive to TCDD and less sensitive to PCBs than those used in the recently published study.…”

Carcinogenic risks of dioxin: Mechanistic considerations

“…Importantly, the results obtained in these studies varied between exposure scenarios where only dioxin-like agents were combined and scenarios where mixtures between dioxin-like and non-dioxin-like chemicals were used. A perfect additive behavior in induction of CYP1A (EROD) activity was observed when using a mixture of potent dioxin-like PCBs, both in hepatocytes and in hepatoma cells in vitro (Schmitz et al, 1995). This result is in good agreement with earlier Wndings of the group using the same end-point but a mixture of diVerent dioxin congeners (Schrenk et al, 1991).…”

Dioxinlike Components in Incinerator Fly Ash: A Comparison between Chemical Analysis Data and Results from a Cell Culture Bioassay

“…The concept of I-TEFs is based on the assumption that the dioxinlike effects of the individual congeners are additive. Moreover, EROD-TEF values of PCDDs (19) and PCBs (21) in the bioassay were in very good agreement with I-TEFs and WHO-TEFs, respectively. However, the fact that most if not all toxic effects of TCDD and related compounds are mediated by a common receptor, the dioxin or aryl hydrocarbon receptor (AhR), is in favor of the concept of additivity (5,7,13).…”

In vitro induction of CYP1A1-associated activities in human and rodent cell lines by commercial and tissue-extracted halogenated aromatic hydrocarbons

“…The greater sensitivity of H4IIE and the order of PCB congener potency relative to TCDD are consistent with the comparative toxic and biochemical potencies reported in the literature [1,2,5,7,20]. The differences in sensitivity and potency are also consistent with recently published results for the induction of EROD activity in H4IIE [30]. Interestingly, the H4IIE cells used in our study seem to be more sensitive to TCDD and less sensitive to PCBs than those used in the recently published study.…”

Carcinogenic risks of dioxin: Mechanistic considerations

“…Importantly, the results obtained in these studies varied between exposure scenarios where only dioxin-like agents were combined and scenarios where mixtures between dioxin-like and non-dioxin-like chemicals were used. A perfect additive behavior in induction of CYP1A (EROD) activity was observed when using a mixture of potent dioxin-like PCBs, both in hepatocytes and in hepatoma cells in vitro (Schmitz et al, 1995). This result is in good agreement with earlier Wndings of the group using the same end-point but a mixture of diVerent dioxin congeners (Schrenk et al, 1991).…”

Dioxinlike Components in Incinerator Fly Ash: A Comparison between Chemical Analysis Data and Results from a Cell Culture Bioassay

“…The concept of I-TEFs is based on the assumption that the dioxinlike effects of the individual congeners are additive. Moreover, EROD-TEF values of PCDDs (19) and PCBs (21) in the bioassay were in very good agreement with I-TEFs and WHO-TEFs, respectively. However, the fact that most if not all toxic effects of TCDD and related compounds are mediated by a common receptor, the dioxin or aryl hydrocarbon receptor (AhR), is in favor of the concept of additivity (5,7,13).…”