Genotype-specific reduction in methyl nitrosourea (MNU) induced sister chromatid exchanges (SCE) in vivo during aging.
We studied mice from five strains (BALB/c, C3H/HeSnJ, C57BL/6J, Csb and 129/ReJ) at two ages (young, 10 +/- 1 weeks; and old, 67 +/- 3 weeks) for the induction of sister chromatid exchanges (SCEs) in vivo by methyl nitrosourea (MNU). The SCE frequency is genotype-specific. The F1 phenotype resembles the 'low' responding parent. SCE induction is significantly lower in the older animals of each strain than their younger counterparts, and the reduction of SCE/cell with old age is strain-specific. A general explanation for these results must include strain differences in relative mutagenic sensitivity, genotype-specific pattern of reduction in DNA repair and other such factors affecting SCE formation, with old age.
Department of Zoology, Children's Hospital of Western Ontario, University of Western Ontario, London, Canada.
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D000375:Aging; D000818:Animals; D001835:Body Weight; D004249:DNA Damage; D004260:DNA Repair; D004305:Dose-Response Relationship, Drug; D005838:Genotype; D008770:Methylnitrosourea / Q000494:pharmacology*; D051379:Mice; D008815:Mice, Inbred Strains / Q000235:genetics*; D012854:Sister Chromatid Exchange / Q000187:drug effects*
D008770:Methylnitrosourea