Pathogenesis of 1,2-dimethylhydrazine-induced carcinomas in rat intestine. I. The induction of mucin producing carcinomas in rat intestine.

Seventy four white male Wistar rats were divided into two groups and given weekly subcutaneous injections of 30 mg 1,2-dimethylhydrazine (DMH) 2HC1/kg body weight for 10 or 15 weeks, respectively, and the histological properties and distribution of DMH-induced rat carcinomas were investigated. The carcinomas induced by DMH were classified mainly into mucin producing carcinomas and non-mucin producing ones. In the large intestine, the group treated for 15 weeks induced significant incidences of mucin producing carcinomas composed mainly of cells containing intracellular mucin. Mucin producing carcinomas consisted of poorly differentiated adenocarcinoma, signet ring cell carcinoma and mucinous carcinoma, and these often coexisted within the same tumor mass. Mucin producing carcinomas tended to develop in the proximal colon and caecum, while non-mucin producing carcinomas were frequent in the distal colon. This method was thought to be a useful model to study glycoproteins of cancer cells.