Experimental carcinoma of the biliary tract induced in dogs by N-ethyl-N'-nitro-N-nitrosoguanidine.

The present study was designed to produce the experimental carcinoma of the biliary tract in dogs. Tube cholecystostomy was constructed in 8 mongrel dogs and 5-10 ml of 0.7-1.0 mg/ml solution of N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG) was administered through the tube every day for the maximum period of 180 days. As the results: The experiment had to be cut off in 7 dogs (5 dogs: The tube was inadvertently pulled out. 2 dogs: died of general weakness). Pathological changes were observed in one dog given ENNG for 180 days and sacrificed at 372 days after the beginning of the experiment. Macroscopically, scattered foci of flat elevation of the mucosa were observed in the entire mucosal surface of common bile duct and a tiny polypoid lesion at the terminal protion. A tiny polypoid projection was adenocarcinoma confined to the mucosa, and areas of flat elevation showed marked hyperplasia of mucosa with partial atypical proliferation. No remarkable findings were noted in other organs.