Otto H F, Winkler R, Heitmann C
Z Krebsforsch Klin Onkol Cancer Res Clin Oncol. 1976 Dec 9;87(3):333-42. doi: 10.1007/BF00506507.
The morphogenesis of neoplasms (carcinomas and pracecancerous polypoid lesions) induced by N-methyl-N-nitroso-N'-nitroguanidine (MNNG) was studied on 154 male Wistar rats (including controls), from which a group received a colostomy. Operated and non-operated rats were treated by intrarectal instillations of 2 mg per kg body weight MNNG twice a week during a period of 210 days.