Focal suppression and induction of hyperplasia by the bladder carcinogens butyl(4-hydroxybutyl)nitrosamine and buty(3-carboxypropyl)nitrosamine in organ-cultured rat bladder epithelium.

The effects of the bladder carcinogens butyl(4-hydroxybutyl)nitrosamine (BBN) and butyl(3-carboxypropyl)-nitrosamine (BCPN) on proliferating transitional rat epithelium in organ culture were studied. At low to intermediate concentration ranges (0.5--2.9 mM), both compounds appeared to stimulate hyperplasia in some regions of epithelia. The major effect of both carcinogens, however, was to suppress hyperplasia in other regions of epithelia and, at higher concentrations (5--6 mM), to cause necrosis. For comparable concentrations, BBN was more effective in suppressing proliferation and causing necrosis than was BCPN.