ABSTRACT
Various in vivo animal models using different agents and different species of animals are being used to study the various aspects of large intestinal carcinoma. This chapter discusses some of the models that have been popularly used in the study of large intestinal carcinomas. Aflatoxins B1 (AFB1) was either administered orally by mixing it to casein or by gastric intubation by dissolving AFB1 in dimethylsulfoxide. H. J. Spjut and M. W. Noall induced adenocarcinomas and “adenomatous polyps” of the large intestine by daily subcutaneous injections of 3,2'-Dimethyl-4-Aminobiphenyl. Histogenesis of colon carcinoma was studied by Lev and Herp who used a 2- and 2.5-mg dosage of N-Methyl-N-Nitrosourea per week by intrarectal injection. Most of the induced neoplasms that appeared polypoid by gross examination were invasive, well-differentiated adenocarcinomas. Although N-Methyl N'-Nitro-N-Nitrosoguanidine is a potent carcinogen, it takes a very long time to get desired carcinogenic changes in vivo.
