Toh Y C
Carcinogenesis. 1981;2(11):1219-21. doi: 10.1093/carcin/2.11.1219.
BALB/c mice were castrated at 2 days of age and control animals were sham-operated. Untreated male and female mice were also included for comparison. One-half of the mice in each group were fed on alternate days with 1.5% N-2-fluorenylacetamide suspended in 1% gelatine by stomach tube beginning at 1 week of age for a total of 14 feedings. The experiment was terminated when the mice reached one year old. Approximately 30% of the male mice, but none of the females, developed liver tumors in groups fed carcinogen. This male predominance in the incidence of hepatocellular carcinomas was completely abolished when the animals were castrated neonatally. No lesions were observed in the liver of mice treated with gelatine suspension alone except one with neoplastic nodule. Although it has been observed that liver tumors are produce more readily in younger than in older mice, the present investigation shows that male hormonal environment during early life is more important than the age on the development of liver tumors initiated by carcinogen.
BALB/c小鼠在2日龄时进行去势手术，对照动物进行假手术。还纳入了未处理的雄性和雌性小鼠用于比较。每组中的一半小鼠从1周龄开始每隔一天通过胃管喂食悬浮于1%明胶中的1.5% N-2-芴基乙酰胺，共喂食14次。当小鼠达到1岁时实验终止。在喂食致癌物的组中，约30%的雄性小鼠发生了肝肿瘤，但雌性小鼠无一发生。当动物在新生期去势后，肝细胞癌发病率的这种雄性优势完全消失。单独用明胶悬液处理的小鼠肝脏中除一只出现肿瘤结节外未观察到病变。尽管已经观察到幼年小鼠比成年小鼠更容易产生肝肿瘤，但本研究表明生命早期的雄性激素环境对致癌物引发的肝肿瘤发展比年龄更重要。
