Benzo[a]pyrene metabolizing activity of cultured cells as determined by a simplified radiometric method

Benzo[a]pyrene metabolism in various kinds of mammalian cultured cells was measured by a simplified method. Cells growing in the bottom of glass test tubes were treated with 2micron of 14C-benzo[a]pyrene for 24 hr; unmetabolized benzo[a]pyrene was then extracted with organic solvents in the same test tube, and the amount of water-soluble products recovered in the aqueous phase was measured by a liquid scintillation counter. Among rodent embryo cells, embryo cells of C3H/He mice and Syrian hamsters showed a higher activity in benzo[a]pyrene metabolism than those of DDD, AKR, and C57BL/6 mice. Several cell line sensitive to density-dependent inhibition, such as Y-AK, DL1, and C3H/10T1/2, actively metabolized benzo[a]pyrene to water-soluble products. The metabolizing activity of C3H/He mouse embryo cells was markedly enhanced by pretreatment with benz[a]anthracene. tthe amount of water-soluble products by phytohemagglutinin-stimulated human lymphocytes was much less than that by most cultured cell lines and embryo cells, but clearly increased with extension of culture days.