N-Butyl-N-(4-hydroxybutyl)nitrosamine was given to male Wistar rats at a dose of 0.05% in the drinking water for one to five weeks, and agglutination of cells isolated from their bladder by concanavalin A (Con A) was determined at intervals during and after treatment. Mucosal cells were isolated from everted bladder by ethylenediaminetetraacetate treatment and sonication. As early as one week after the start of treatment, Con A caused some agglutination of isolated bladder cells, and this agglutination increased with time, reaching an almost constant value from the third week. Con A agglutination of bladder cells induced by N-butyl-N-(4-hydroxybutyl)nitrosamine treatment for only one week appeared to be irreversible, and it was still observed two weeks after the end of treatment. Scanning electron microscopy showed that microvilli developed on the luminal surface of mucosal cells in situ at the time when the isolated cells became agglutinable with Con A. Measurement of agglutinability of isolated bladder cells with Con A might be a useful way of detecting very early changes in bladder carcinogenesis.
Supported in part by Grants-in-Aid from the Ministry of Health and Welfare, the Ministry of Education, Science, and Culture, and the Society for Promotion of Cancer Research, Japan.