Comparison of sister chromatid exchanges in spleen and thymus lymphocytes from AKR, C57BL/6N x DBA/2J F1, and CBA mice following in vivo exposure to N-methyl-N-nitrosourea.
The induction of sister chromatid exchange (SCE) by N-methyl-N-nitrosourea (MNU) was studied in spleen and thymus lymphocytes from AKR mice, which are highly susceptible to MNU-produced thymomas, CBA mice, which are much less sensitive to induction of thymomas by MNU, and C57BL/6N x DBA/2J F1 mice. MNU produced dose-related increases in SCE in concanavalin A (Con A)- and lipopolysaccharide-stimulated spleen lymphocytes and Con A-stimulated thymus lymphocytes from each mouse strain at 1 and 24 h posttreatment. MNU-induced SCE were generally higher in Con A-stimulated spleen lymphocytes compared to lipopolysaccharide-stimulated spleen lymphocytes and Con A-stimulated thymus lymphocytes from each mouse strain. On the whole, MNU-produced SCE were lower in AKR and CBA spleens than in C57BL/6N x DBA/2J F1 spleens. In addition, MNU-induced SCE levels in thymus lymphocytes from all three strains of mice were, for the most part, similar. These results indicate that if differences in MNU-induced genotoxicity in AKR, CBA, and C57BL/6N x DBA/2J F1 thymus lymphocytes exist, these differences cannot be ascertained by use of the in vivo/in vitro SCE assay.
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Division of Genetic Toxicology, Food and Drug Administration, Jefferson, Arkansas 72079.
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Casciano
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D000818:Animals; D002453:Cell Cycle; D003208:Concanavalin A / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D008770:Methylnitrosourea; D051379:Mice; D008806:Mice, Inbred AKR / Q000235:genetics*; D008810:Mice, Inbred C57BL / Q000235:genetics*; D008808:Mice, Inbred CBA / Q000235:genetics*; D008811:Mice, Inbred DBA / Q000235:genetics*; D012854:Sister Chromatid Exchange / Q000187:drug effects*; D013045:Species Specificity; D013154:Spleen; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects; D013950:Thymus Gland; D013997:Time Factors
D008070:Lipopolysaccharides; D003208:Concanavalin A; D008770:Methylnitrosourea