Uterine Carcinogenesis by Chemicals/Hormones in Rodents

It has been demonstrated that the Donryu rat is a high incidence strain for spontaneous development of endometrial adenocarcinomas, associated with a hormonal imbalance. This provides a good model for endometrial adenocarcinoma development in women. An elevated sensitivity to induction of such tumors in this rat strain by a single intra-uterine administration of N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG) has also been shown. Endometrial adenocarcinomas can similarly be induced in CD-1 mice by an intra-uterine administration of N-ethyl-N-nitrosourea (ENU) and subcutaneous implantation of 17β-estradiol pellets. These animal systems have allowed two-stage uterine carcinogenicity studies in rodents. In this paper, spontaneous occurrence of uterine tumors, uterine carcinogenesis by chemicals and/or hormones and the influence of several factors on occurrence of uterine tumors in rodents are reviewed and discussed, with the main focus on our own present data.