Molecular dosimetry of sister chromatid exchange induction in 9L cells treated with 6-thioguanine.
The induction of sister chromatid exchanges (SCE) in 9L cells treated with 6-thioguanine (6-TG) has been investigated. A 24 h treatment with 0.2 microM 6-TG induced approximately 28 SCE/metaphase. The dose-response curve was linear at doses below 0.2 microM and had a slope of 139 SCE/metaphase/microM 6-TG. At concentrations of 0.023 to 1 microM, incorporation of 6-TG in DNA was linear with dose. The slope of the dose-response curve was 4135 mumol 6-TG/mol DNA/microM 6-TG. Comparison of these results with those obtained in our previous studies of the monofunctional alkylating agent ethylnitrosourea and the bifunctional alkylating agent 3-(4-amino-2-methyl-5-pyrimidinyl)methyl-1-(2-chloroethyl)-1-nitrosourea suggest that to accurately estimate the effectiveness of particular DNA modifications at inducing SCE, the extent of formation of these DNA modifications must be known.
Bodell
W J
WJ
Department of Neurological Surgery, School of Medicine, University of California, San Francisco 94143.
D000477:Alkylating Agents / Q000494:pharmacology; D000818:Animals; D004249:DNA Damage; D004305:Dose-Response Relationship, Drug; D005038:Ethylnitrosourea / Q000494:pharmacology; D005910:Glioma / Q000235:genetics / Q000473:pathology; D015376:Nimustine / Q000494:pharmacology; D051381:Rats; D012854:Sister Chromatid Exchange / Q000187:drug effects*; D013866:Thioguanine / Q000494:pharmacology*; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000648:ultrastructure
D000477:Alkylating Agents; D015376:Nimustine; D013866:Thioguanine; D005038:Ethylnitrosourea