High Susceptibility of an Analbuminemic Congenic Strain of Rats with an F344 Genetic Background to Induced Bladder Cancer and Its Possible Mechanism

The susceptibility of an analbuminemic congenic strain of rats (F344‐alb) originating from the F344 strain to N‐butyl‐N‐(4‐hydroxybutyl)nitrosamine (BBN) was examined. F344‐alb rats were found to be highly susceptible to induction of urinary bladder cancers. The incidences of bladder cancers in F344‐alb and F344 rats were 94% (15/16) and 31% (5/16) in males and 100% (16/16) and 19% (3/16) in females. The bladder weights of these rats, including tumors, were 307±294 mg, 123±26 mg, 183±80 mg and 93±11 mg, respectively. Administration of 0.05%, 0.1% and 0.3% BBN in the drinking water for 2 weeks resulted in greater increases in the bladder content of N‐butyl‐N‐(3‐carboxypropyl)nitrosamine in F344‐alb rats than in F344 rats. This increase was prevented by the presence of rat albumin.