Polycyclic aromatic hydrocarbon in vitro cytotoxicity to bluegill BF-2 cells: mediation by S-9 microsomal fraction and temperature.

The in vitro cytotoxicities of various polycyclic aromatic hydrocarbons (PAHs) to bluegill sunfish BF-2 cells were determined with the neutral red assay, which was modified by the incorporation of an S-9 microsomal fraction. Whereas the PAHs per se were weakly cytotoxic, the presence of the S-9 fraction in the incubation mixture increased the cytotoxicity of many of the PAHs, presumably due to the formation of active metabolites. In addition, the cytotoxicity of the PAHs (whether in the absence or presence of the S-9 microsomal fraction) was potentiated if the 6 h exposure was at 37, rather than at 26 degrees C.