Beland F A, Dooley K L, Sheldon W G, Delongchamp R R
National Center for Toxicological Research (NCTR), Jefferson, AR 72079.
J Natl Cancer Inst. 1988 May 4;80(5):325-30. doi: 10.1093/jnci/80.5.325.
Male C57BL/6N mice were administered a single ip injection of 30 mg of N-methyl-N-nitrosourea (MNU)/kg of body weight. Additional groups were treated similarly every 3 hours for the next 24 hours. Adenocarcinomas of the small intestine were the major treatment-related tumors, with the total incidence being 38% at 250 days after injection. There was a significant circadian variation for tumor induction; the maximum number of intestinal tumors (approximately equal to 55%) tended to occur when the MNU was administered during the middle of the light period (6:00 to 18:00), while the tumor incidence was at a minimum (approximately equal to 10%) when the MNU was given in the middle of the dark phase (18:00 to 6:00). These data are discussed in relation to DNA synthesis and repair and MNU-induced cellular toxicity.
给雄性C57BL/6N小鼠腹腔注射一次30毫克/千克体重的N-甲基-N-亚硝基脲（MNU）。在接下来的24小时内，每隔3小时对其他组进行类似处理。小肠腺癌是主要的与治疗相关的肿瘤，注射后250天时总发病率为38%。肿瘤诱导存在显著的昼夜变化；当在光照期中期（6:00至18:00）给予MNU时，肠道肿瘤的最大数量（约等于55%）倾向于出现，而当在黑暗期中期（18:00至6:00）给予MNU时，肿瘤发病率最低（约等于10%）。结合DNA合成与修复以及MNU诱导的细胞毒性对这些数据进行了讨论。
