Effect of Leupeptin, a Protease Inhibitor, on Induction of Bladder Tumors in Rats by N-Butyl-N- (4-hydroxybutyl ) nitrosamine

Summary

Leupeptin, isolated from Actinomycetes, is a potent and specific inhibitor of proteases. We found that the administration of leupeptin enhanced the size of urinary bladder tumors induced in rats by the oral administration of N-butyl-N( 4-hydroxybutyl)nitrosamine (BBN). BBN was given as a 0.05% solution in the drinking water for 6 weeks, and then animals were fed a diet with or without 0.1% leupeptin for 30 weeks. The average weight of the bladders with tumors in rats fed a leupeptin diet was about eight times that of rats on a diet without leupeptin, though the incidences and average numbers of tumors in the bladders were similar in the two group.