Enhancing effect of 2,3,4,7,8-pentachlorodibenzofuran and 1,2,3,4,7,8-hexachlorodibenzofuran on diethylnitrosamine hepatocarcinogenesis in rats.

Enhancement of diethylnitrosamine(DENA)-induced hepatic tumor production in rats was observed by sequential exposure to 2,3,4,7,8-pentachlorodibenzofuran (PenCDF) or 1,2,3,4,7,8-hexachlorodibenzofuran (HCDF). This effect was more evident in the group of rats treated with 2,3,4,7,8-PenCDF (80 micrograms/rat), in which approximately 43% of this compound administered was accumulated in the liver at 8 weeks after the last treatment.