Inhibition of the binding of 7,12-dimethylbenz[a]anthracene to DNA by ascorbic acid, reduced glutathione and cysteine in chick embryo cells cultured in vitro.

A study on the capacity of ascorbic acid, reduced glutathione and cysteine to interfere with 3H-7,12-dimethylbenz[a]anthracene (3H-DMBA) binding to DNA in cultured fibroblast-like cells from 11-day-old chick embryos showed that, although the total amount of 3H-DMBA in the treated cells was greater than in the untreated cells, the DNA-bound 3H-DMBA was less. Comparisons between the various experimental groups demonstrated that the greater 3H-DMBA in the ascorbic acid-, reduced glutathione-, and cysteine-treated groups could not be attributed to an initially higher number of cells, nor to a treatment-induced increase in DNA synthesis. It is proposed that the three substances examined inhibit the oxidative degradation of 3H-DMBA, thereby favoring its accumulation within the cell and reducing the formation of DNA-binding metabolites.