Novel variants in benzo(a)pyrene metabolism. Isolation by fluorescence-activated cell sorting.

We have used the fluorescence-activated cell sorter to measure the metabolism of the carcinogenic polycyclic aromatic hydrocarbon, benzo(a)pyrene (BP), in individual, viable mouse hepatoma (Hepa 1c1c7) cells and to physically select variants with either markedly elevated or markedly decreased ability to metabolize to low, nontoxic concentrations of BP (25 nM) and measuring the rate of disappearance of BP fluorescence. We show by several criteria that the disappearance of BP fluorescence is due to the metabolism of the carcinogen. Cells sorted according to their rae of loss of BP fluorescence exhibit the predicted phenotypes in BP-metabolizing activity, as measured by the aryl hydrocarbon hydroxylase assay.