Ito A, Takahashi T, Watanabe H, Ogundigie P O, Okamoto T
Department of Cancer Research, Hiroshima University.
Jpn J Cancer Res. 1992 Oct;83(10):1052-6. doi: 10.1111/j.1349-7006.1992.tb02721.x.
Mouse liver tumors occurring in C3H/HeN, C57BL/6N and C3B6F1 hybrid (C3H x C57BL) were studied following 252Cf fission neutron irradiation. Three strains of mice of both sexes (about 30 mice/group) were irradiated once with 252Cf at doses of 0, 12.5, 50 and 200 cGy. The groups were observed for 13 months after irradiation. The incidence of liver tumors in the non-irradiated controls was 0% in both sexes of C57BL/6N, 11.7% in males and 0% in females of C3B6F1 and 39.5% in males and 11.4% in females of C3H/HeN mice. In the four strains of mice thus far studied, including B6C3F1 hybrid (C57BL x C3H) which was previously studied, 252Cf irradiation has increased the tumor incidence dose-dependently in males and in females, but less effectively in females. The mean number and size of liver tumors were clearly correlated with tumor incidence. The incidence was always highest in C3H/HeN mice of both sexes, followed by B6C3F1, C3B6F1 and C57BL/6N mice. The influence of sex hormones was studied in B6C3F1 mice of both sexes after 200 cGy of 252Cf irradiation. In males, the incidence of liver tumors was significantly decreased from 55.2% to 23.3% and 25.9% after orchidectomy, and in females it was slightly decreased from 27.6% to 14.8% and 18.8% after ovariectomy. Supplementation of testosterone in orchidectomized mice did not restore the occurrence of liver tumors.
对252Cf裂变中子辐照后C3H/HeN、C57BL/6N和C3B6F1杂交种（C3H×C57BL）小鼠发生的肝脏肿瘤进行了研究。将两性的三株小鼠（每组约30只）分别用剂量为0、12.5、50和200 cGy的252Cf辐照一次。辐照后对这些组观察13个月。未辐照对照组中，C57BL/6N两性的肝脏肿瘤发生率均为0%，C3B6F1雄性为11.7%、雌性为0%，C3H/HeN雄性为39.5%、雌性为11.4%。在迄今研究的四株小鼠中，包括之前研究过的B6C3F1杂交种（C57BL×C3H），252Cf辐照使雄性和雌性肿瘤发生率呈剂量依赖性增加，但对雌性的作用较小。肝脏肿瘤的平均数量和大小与肿瘤发生率明显相关。两性C3H/HeN小鼠的发生率始终最高，其次是B6C3F1、C3B6F1和C57BL/6N小鼠。对200 cGy 252Cf辐照后的B6C3F1两性小鼠研究了性激素的影响。雄性小鼠去势后，肝脏肿瘤发生率从55.2%显著降至23.3%和25.9%，雌性小鼠卵巢切除后从27.6%略有降至14.8%和18.8%。去势小鼠补充睾酮并未恢复肝脏肿瘤的发生。
