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.
Bond
S L
SL
Department of Zoology, Children's Hospital of Western Ontario, University of Western Ontario, London, Canada.
Singh
S M
SM
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