Damage to and repair of DNA isolated from human neonatal and fetal skin cells were measured by alkaline sucrose gradient analysis. 3-Methylcholanthrene did not induce single-strand breaks in DNA of the cells in culture, whereas the 11,12-oxide of 3-methylcholanthrene was very effective in this regard. The cis-1,2-dihydroxy, trans-11,12-dihydroxy, and cis-11,12-dihydroxy derivatives of 3-methylcholanthrene exerted little effect. The breaks in DNA caused by 3-methylcholanthrene oxide occurred during a 60-min incubation period and were repaired during the following 60 min. Methylmethane sulfonate also induced breaks in the DNA within 60 min.


Supported in part by grants from the American Cancer Society (BC 188) and the NIH (CA 12906-03).

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