[Effect of carcinogenic 2-naphthylamine on organ cultures of the urinary bladder of the rat].

Treatment with 2-naphthylamine was followed by an 1.5-3 fold increase in the frequency of hyperplastic changes in the organ culture cells of rat urinary bladder epithelium, as compared with intact control and cell cultures treated with a non-carcinogenic analog (30.8, 17.6 and 10.7%, respectively). It is suggested that this effect was associated with the initial specific blastogenic effect of 2-naphthylamine metabolites on rat urothelium, the latter being traditionally considered resistant to this agent. Some other factors absent in rats but present in humans and dogs are indispensable for further malignant transformation and tumorigenesis.