Abstract
Enhancing effects of bladder carcinogens or promoters on the early development of neoplastic or putative preneoplastic epithelial lesions in the rat bladder were investigated. The rats were given 0.05% N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN) in drinking water for 4 weeks, and then fed test chemical during experimental weeks 5 to 9 (5 weeks) and weeks 13 to 20 (8 weeks). In addition, during weeks 10 to 12 (3 weeks), the rats were fed 3% uracil in diet. Rats in a control group were treated with BBN and uracil. The total observation period was 20 weeks. Significantly higher numbers of papillary or nodular hyperplasia in the bladder were observed in all test chemical treated-groups [3, 3'-dichlor-obenzidine, N, N-dibutylnitrosamine (DBN), N-methyl-N-nitrosourea (MNU), sodium o-phenyl-phenate (SOPP), and sodium saccharin (SS)] after BBN treatment. Incidences or numbers of papilloma were significantly increased in the groups of rats treated with DBN, MNU, SOPP or SS, and those of carcinoma were increased in the groups treated with.DBN or SOPP. These results suggest that this system might be useful for the more rapid detection of bladder carcinogens and promoters.
