[Experimental administration of di-N-butyl-nitrosamine (DBN) in rats. Carcinogenic activity in the urinary bladder]

Di-N-butyl-nitrosamine (DBN) was administered in a suspension with dimethylsulfoxide (DMSO) to 80 rats in doses of 10 and 40 mg/kg/day. The carcinogen was given to the animals in groups of 40 either orally or subcutaneously. The animals were exposed to the carcinogen for a maximum of 320 days. In one group of animals, hypertrophia and hyperplasia affected the whole epithelium of the bladder. In the other group, hyperplasia was intense enough to be considered as carcinomatous. A third group developed papillomatous carcinomas, which occupied the whole interior of the bladder.