L-isoleucine and L-leucine: tumor promoters of bladder cancer in rats.
A 4-week assay for screening tumor promoters of bladder cancer has been developed in which increased agglutinability of isolated rat bladder cells with concanavalin A is used as an indicator. On the basis of this assay system, L-isoleucine and L-leucine were suspected of being possible tumor promoters. Results of 40- to 60-week carcinogenesis experiments in which N-butyl-N-(4-hydroxybutyl)nitrosamine was used as an initiator demonstrate that L-isoleucine and L-leucine promote bladder cancer in rats. This finding may be relevant to the high incidence of human bladder cancer in Western countries, where the diet is rich in protein.
D000818:Animals; D002273:Carcinogens; D002277:Carcinoma / Q000139:chemically induced*; D007532:Isoleucine; D007930:Leucine; D010212:Papilloma / Q000139:chemically induced*; D011230:Precancerous Conditions / Q000139:chemically induced*; D051381:Rats; D011916:Rats, Inbred F344; D001749:Urinary Bladder Neoplasms / Q000139:chemically induced*
D002273:Carcinogens; D007532:Isoleucine; D007930:Leucine