Dimethyl sulfoxide-induced enhancement of 7,12-dimethylbenz(a)anthracene metabolism and DNA binding in differentiating mouse epidermal cell cultures.

Mouse epidermal cells in primary culture differentiate rapidly over a 2-week period leading to keratinization and sloughing of most of the plated cells. Cell replication was partially synchronized in these cultures with peaks of DNA synthesis at the 2nd and 8th day. The ability of epidermal cells to metabolize 7,12-dimethylbenz[a]anthracene and the subsequent binding of activated products to epidermal DNA was a function of the culture time. Constitutive and induced levels of aryl hydrocarbon hydroxylase in cells cultured for 10 days were half of those in cells grown for 3 days. Likewise, 7,12-dimethylbenz[a]anthracene binding to epidermal DNA was two- to fourfold lower in 10-day than 3-day cultures. This decrease in metabolism and binding between 3-day and 10-day cultures could be eliminated by the inclusion of 1.25% dimethyl sulfoxide in the culture medium during the entire culture period.