BD-II and BD-IX male and female rats received weekly subcutaneous (s.c.) injections of 15 mg/kg 1,2-dimethylhydrazine dihydrochloride (DMH) beginning at either 35, 120 or 210 days of age and continuing for 20 weeks. Control animals received only the DMH vehicle. Additional BD-II and BD-IX male and female rats of the three age groups were gonadectomized at 21, 106 and 196 days. Beginning 14 days after gonadectomy, the rats received 15 mg/kg of DMH by s.c. injection once a week for 20 weeks. Animals were sacrificed 35 weeks after the initial DMH injection. Control rats of the appropriate age and sex did not develop colon tumors. BD-IX rats are apparently more sensitive to DMH than BD-II rats. The incidence of DMH-induced cancer is less in females than in males in both the BD-II and BD-IX animals. Gonadectomy does not affect cancer incidence in either BD-II males or females nor in the BD-IX females but reduced the incidence in BD-IX males exposed initially at either 120 or 210 days. Administration of androgen to castrate BD-IX males (120-day-old group) increases the incidence of colon cancer to that approaching the intact animal but has little effect in the BD-II castrate male. These data suggest a genetically influenced susceptibility to DMH-induced colon carcinogenesis between BD-II and BD-IX rats. Furthermore, a sex difference is evident in both BD lines but age appears to be a factor only in older BD-IX females. Apparently, androgens influence DMH-induced tumorigenesis in BD-IX males only if the initial exposure of DMH occurs after sexual maturity.

译文

bd-ii和bd-ix雄性和雌性大鼠每周接受15 mg/kg 1,2-二甲基肼二盐酸盐 (DMH) 的皮下 (s.c.) 注射,从35、120或210日龄开始,持续20周。对照动物仅接受DMH运载工具。在21、106和196天时对三个年龄组的其他bd-ii和bd-ix雄性和雌性大鼠进行性腺切除。从性腺切除术后14天开始,大鼠接受了15 mg/kg的DMH。每周注射一次,持续20周。在最初的DMH注射后35周处死动物。适当年龄和性别的对照大鼠没有发展为结肠肿瘤。Bd-ix大鼠显然比bd-ii大鼠对DMH更敏感。在bd-ii和bd-ix动物中,女性中DMH诱发的癌症的发生率均低于男性。性腺切除术不影响bd-ii男性或女性或bd-ix女性的癌症发病率,但降低了最初在120天或210天暴露的bd-ix男性的发病率。对去势的bd-ix雄性 (120天大组) 施用雄激素可增加结肠癌的发生率,使其接近完整动物,但对bd-ii去势的雄性几乎没有影响。这些数据表明,在BD-II和BD-IX大鼠之间,对DMH诱导的结肠癌发生的遗传易感性受到影响。此外,两个BD系的性别差异都很明显,但年龄似乎仅是年龄较大的bd-ix女性的一个因素。显然,只有当DMH的初次暴露发生在性成熟后,雄激素才会影响bd-ix男性中DMH诱导的肿瘤发生。

+1
+2
100研值 100研值 ¥99课程
检索文献一次
下载文献一次

去下载>

成功解锁2个技能,为你点赞

《SCI写作十大必备语法》
解决你的SCI语法难题!

技能熟练度+1

视频课《玩转文献检索》
让你成为检索达人!

恭喜完成新手挑战

手机微信扫一扫,添加好友领取

免费领《Endnote文献管理工具+教程》

微信扫码, 免费领取

手机登录

获取验证码
登录