1. Supplemental Effect of 1,2-Dimethylhydrazine on Methylazoxymethanol Acetate-induced Colon Carcinogenesis in Rats; Effect of .ALPHA.-difluoromethylornithine on the Progression of Tumorigenesis
- Author
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Naoki Yoshimi, Masahito Shimizu, Hideki Mori, Kengo Matsunaga, Yukio Morishita, Kunihiro Kawabata, and Yasuhiro Yamada
- Subjects
Pathology ,medicine.medical_specialty ,Methylazoxymethanol acetate ,Colorectal cancer ,business.industry ,Toxicology ,medicine.disease_cause ,medicine.disease ,Pathology and Forensic Medicine ,Colon carcinogenesis ,1,2-Dimethylhydrazine ,chemistry.chemical_compound ,Endocrinology ,chemistry ,Internal medicine ,medicine ,Atypia ,Lymph ,Carcinogenesis ,Intestinal Cancer ,business - Abstract
In the present study, establishment of a rat model for progression in the large bowel carcinogenesis by combined exposure of methylazoxymethanol (MAM) acetate and 1,2-dimethylhydrazine (DMH) was tried, and the modifying effect of α-difluoromethylornithine (DFMO), a chemopreventive agent, was examined in this model. A total of 200 F344 male rats were divided into 8 groups. At 6 weeks of age, the rats of Groups 1 (30 rats), 2 (30 rats), 3 (30 rats), and 4 (30 rats) were given i.p. injections of MAM acetate (20 mg/kg body weight) once a week for 3 weeks. Sixteen weeks after the first injection of MAM acetate, the rats of Groups 3, 4, 5 (20 rats), and 6 (20 rats) received s.c. injections of DMH (20 mg/kg body weight) once a week for 10 weeks. Fifteen weeks after the first treatment of MAN acetate, the rats of Groups 2, 4, 6, and 7 (20 rats) were exposed to DFMO in drinking water at a concentration of 0.1%. Group 8 (20 rats) was served as an untreated control. The incidence of colon cancer of Group 3 (MAM→DMH, 62%) was higher than that of Group 1 (MAM alone, 31%, P
- Published
- 1998