Agglutination by concanavalin A of urothelial cells of heterotropically transplanted rat urinary bladders: effect of bladder carcinogens and urine

Abstract

N-butyl-N-(3-carboxypropyl)nitrosamine (BCPN) has been considered to be a carcinogenic urinary metabolite of N-butyl-N-(4-hydroxybutyl)nitrosamine. No tumor developed, however, in the heterotropically transplanted rat urinary bladders (HTBs) following repeated instillation of BCPN dissolved in physiological saline. In the present study, the possibility that BCPN dissolved in urine may induce tumors was explored using a short-term screening assay. When tested with the concanavalin A agglutination assay with which a close correlation between increase in cell agglutinability and carcinogenicity of test compounds has been well demonstrated, no significant increase in agglutinability attributable solely to BCPN was observed in HTB cells whether it was dissolved in saline or urine. Based on the current findings together with other available data, it is suggested that urothelial cells have a very limited capability to activate BCPN to the ultimate carcinogen, and require continuous contact with the carcinogen to respond with tumor formation.