- Induction of endometrial adenocarcinomas by a single intra-uterine administration of N-ethyl-N'-nitro-N-nitrosoguanidine to aged Donryu rats showing spontaneously persistent estrus. Takahashi, M., Ando-Lu, J., Yoshida, M., Iijima, T., Ishihara, R., Imai, S., Kitamura, T., Suzuki, K., Nishiyama, K., Nishimura, S. Cancer Lett. (1995)