Carrier effects of dosing the H4IIE cells with 3,3',4,4'-tetrachlorobiphenyl (PCB77) in dimethyl sulfoxide or isooctane.

A rat hepatoma cell line, H4IIE, serves as a bioassay tool to assess the potential toxicity of dioxin-like chemicals, including polychlorinated biphenyls (PCB) in environmental samples. PCB exposure to these cells induces cytochrome (CYP) P4501A1 activity in a dose-dependent fashion, thus allowing assessment of mixtures. The objective of this study was to determine the effect of different carriers, dimethyl sulfoxide (DMSO) and isooctane on the concentrations of PCBs in the H4IIE cells and induction of CYP1A1 activity as measured by ethoxyresorufin O-deethylase (EROD) activity. H4IIE cells were dosed with three micrograms of UL-14C-PCB77/plate dissolved in DMSO or isooctane, and were harvested at sequential time periods for 4 days. PCB77 concentration and EROD activity were measured in the cells. EROD activity was greater when using DMSO as compared to isooctane, while there was no difference in the distribution of PCB77-derived radioactivities within the cell culture system based upon the carrier solvent used to deliver PCB77.