[Experimental teratoma by fetectomy in the rats : influence of ovariectomy (author's transl)].

Forty-six female Sprague-Dawley rats were used. Twelve days after mating, all the fetuses were removed and fetal membrane with yolk sac were left outside of the uterus following the method reported by Sorbis and Vandeputte (1974). About the half of the rats were ovariectomized at the laparotomy. The rats were killed at 20 and 40 weeks after treatment and examined. No difference was observed in tumor incidence between fetectomy alone and fetectomy plus ovariectomy at both 20 and 40 weeks and it was about 70%. The size of tumor varied from 2 to 35 mm in diameter. The size of tumors tended to be greater in fetectomy plus ovariectomy compared with fetectomy alone at 20 weeks, but no significant difference was observed at 40 weeks between the two groups. Histologically the tumors were characterized by the presence of a variety of differentiated tissues. Metastases to the visceral part were detected in 2 rats of fetectomy alone and the tumors were diagnosed as yolk sac tumor. These results indicate that sex steroids might influence the teratocarcinogenesis.