Induction of Carcinomas of the Colon and Rectum in Rats by Intrarectal Instillation of N-Methyl-N'-Nitro-N-Nitrosoguanidine2

Abstract

Adenocarcinomas of the large intestine developed in 30 Sprague-Dawley rats after intrarectal administration of 2 mg N-methyl-N'-nitro-N-nitrosoguanidine/kg body weight twice weekly for 250 days. The tumors were often multiple, and there were 106 nodules in the 30 rats. Metastases were found in the liver, pancreas, and adrenals of 1 rat. In addition to the adenocarcinomas, 1 animal had a squamous cell carcinoma of the anus.