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RELATIVE POTENCY VALUES FOR POLYCHLORINATED DIBENZO-P-DIOXIN, DIBENZOFURAN AND BIPHENYL CONGENERS TO INDUCE CYTOCHROME P4501A MRNA IN A ZEBRAFISH LIVER CELL LINE (ZF-L)
Citation:
Henry, T R., XX, D. J. Nesbit, W. Heideman, AND R. E. Peterson. RELATIVE POTENCY VALUES FOR POLYCHLORINATED DIBENZO-P-DIOXIN, DIBENZOFURAN AND BIPHENYL CONGENERS TO INDUCE CYTOCHROME P4501A MRNA IN A ZEBRAFISH LIVER CELL LINE (ZF-L). ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 20:1053-1058, (2000).
Description:
Induction of cytochrome P450 (CYPIA) mRNA by polychlorinated dibenzo-p-dioxin (PCDD), polychlorinated dibenzofuran (PCDF) and polychlorinated biphenyl (PCB) congeners was measured in a zebrafish liver cell line (ZF-L). ZF-L cells were far less sensitive to PCDD, PCDF and PCB congeners than other fish cell lines. 2,3,7,8-PCDDs, -PCDFs and PCB 126 caused dose-related induction. All other PCBs tested, including other co-planar as well as ortho-substituted congeners, were ineffective at inducing CYPIA. The potency (REP) of each congener that gave a resposnse, relative to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), was determined. The ZF-L cell-derived REPs are similar to other in vitro REPs in that they are generally higher than those derived from in vivo models. Furthermore, they are generally within 5-fold of REPs determined in a variety of rainbow trout systems when the same endpoint in the same tissue are compared. These data indicate that REPs based on molecular and biochemical responses in sensitive and insensitive species are similar, but over estimate relative in vivo toxicity in the rainbow trout. The ZF-L cell-derived REPs expand the database of REPs, providing additional information that will be useful in quantifying the uncertainty associated with applying consensus fish-specific toxic equivalency factors in ecological risk assessment.