The effect of carcinogenic hydrocarbons on rodent and primate cells in vitro

The effect of polycyclic hydrocarbons on rodent and primate cells in vitro was studied using dimethyl sulfoxide as the initial solvent for the hydrocarbons prior to their addition to the cell cultures. Because the dimethyl sulfoxide was not toxic to the cells at a final concentration in which relatively high concentrations of the hydrocarbons remained in solution in the medium, the effects of the compounds could be measured quantitatively. The carcinogenic hydrocarbons, benzpyrene and methylcholanthrene, but not the non‐carcinogenic hydrocarbon, pyrene, inhibited the multiplication of normal embryonic cells from several rodent species. However, concentrations of the carcinogens as high as 10 μg/ml did not affect the growth of virus‐transformed or malignant cells from these species. In contrast to the differential cytotoxic response of normal and malignant rodent cells to the carcinogenic hydrocarbons, the multiplication of normal, as well as transformed, monkey and human cells was not inhibited by benzpyrene or methylcholanthrene at concentrations of 10 to 20 μg/ml. Organ cultures of human embryonic skin initiated and maintained for ten weeks in medium containing 5 μg benzpyrene/ml showed no abnormalities in the growth rate or morphology of the fibroblasts that grew out of the explants.