Watanabe H, Ito A
J Natl Cancer Inst. 1986 May;76(5):865-70.
The influence of x-radiation and N-methyl-N'-nitro-N-nitrosoguanidine [(MNNG) CAS: 70-25-7] on intestinal metaplasia and gastric tumorigenesis was examined in 5-week-old male Crj:CD(SD) rats. The animals were treated either with two 10-Gy fractions of x-rays separated by 3 days for a total of 20 Gy to the gastric region and/or with MNNG orally for 4 months. Simultaneous treatment with x-rays and MNNG (group II) and MNNG only (group IV) induced gastric tumors in the majority of the animals. Sequential treatment with x-radiation and MNNG, either x-ray 2 months prior to MNNG (group I) or MNNG 2 months prior to x-ray (group III), resulted in a lower incidence of gastric tumors as compared with the incidence after treatment with MNNG alone. The frequencies of intestinal metaplasia in the x-irradiated groups (groups I and V) were significantly higher than those in group II, III, or IV. The incidence of intestinal metaplasia and of gastric tumor was inversely proportional. These results indicate that intestinal metaplasia does not play a role in the induction of gastric tumors by MNNG.
在5周龄雄性Crj:CD(SD)大鼠中，研究了X射线和N-甲基-N'-硝基-N-亚硝基胍[(MNNG)，CAS: 70-25-7]对肠化生和胃肿瘤发生的影响。动物接受以下处理：对胃部进行两次10 Gy的X射线照射，间隔3天，总计20 Gy，和/或口服MNNG 4个月。同时接受X射线和MNNG处理（第二组）以及仅接受MNNG处理（第四组）的大多数动物诱发了胃肿瘤。先进行X射线照射，2个月后给予MNNG（第一组）或先给予MNNG，2个月后进行X射线照射（第三组），与单独使用MNNG处理后的发病率相比，胃肿瘤发病率较低。接受X射线照射的组（第一组和第五组）肠化生频率显著高于第二组、第三组或第四组。肠化生和胃肿瘤的发生率呈负相关。这些结果表明，肠化生在MNNG诱发胃肿瘤过程中不起作用。
