[Blastomogenesis in rats induced by transplacental introduction of estrogens].

The increased frequency of tumors of the uterus and testis was observed in old noninbred rats after the transplacental treatment with estrogens. Eleven tumors of the uterus (6.7 +/- 1.9%) were detected in 165 noninbred rats, supplied by the animal farm of the USSR Academy of Medical Sciences, 18 months or longer after pre- and neonatal treatment with diethylstilbestrol, synestrol and sigetin. Those neoplasms included 4 squamous-cell carcinomas of cervix uteri and vagina. 4 myomas, 2 papillomas of the vagina and one endometrial adenocarcinoma. An ovarian adenocarcinoma and an angiosarcoma of the oviduct were found in two animals. These findings were matched by 2 endometrial adenocarcinomas (1.6 +/- 1.1%) and 3 benign ovarian tumors (in two animals) detected in 124 control female rats aged more than two years. The transplacental treatment with sigetin was followed by an increased frequency of interstitial cell tumors of the testis (up to 16.4 +/- 5.0% as compared with 2.2 +/- 1.6% in control) which developed at an earlier stage, too.