Sister chromatid exchange induction in two cell lines.

Sister chromatid exchange (SCE) induction by the procarcinogen benzo (a)-pyrene (BP) was studied using two established cell lines. Chinese hamster ovary (CHO) and Chinese hamster lung (Don) cells were exposed to varying concentrations of BP in the presence and absence of a rat liver metabolizing system. Results showed a significant difference in the abilities of the two cell lines to induce SCE in the absence of liver homogenate. These experiments demonstrate that Don cells are capable of generating active metabolites from biologically inactive procarcinogens presumably due to an inherent metabolizing system which is deficient or absent in CHO cells.