Inhibitory effect of 4,4'-diaminodiphenylmethane on liver, kidney and bladder carcinogenesis in rats ingesting N-ethyl-N-hydroxyethylnitrosamine or N-butyl-N-(4-hydroxybutyl)nitros-amine

The effects of 4,4'-diaminodiphenylmethane (DDPM) administrationin the ‘post-initiation’ stage of liver, kidneyand bladder carcinogenesis were examined in male F344 rats.In experiment I, rats were given drinking water containing 0.1%N-ethyl-N-hydroxyethyl-nitrosamine for 2 weeks then diet containing0.1% DDPM for 32 weeks. In week 3, the right kidney was removed.The incidence of hepatocellular carcinoma was significantlyless in rats given DDPM than in controls. DDPM decreased theincidence and average number/cm² of neoplastic nodules and renalcell tumors of the kidney. In experiment II, rats were given0.01% N-butyl-N-(4-hydroxybutyl)nitrosamine for 4 weeks andthen 0.1% DDPM for 34 weeks in their drinking water. DDPM inhibitedthe induction of papillomas in the bladder. These results indicatethat DDPM administration in the ‘post-initiation’stage inhibited liver, kidney and bladder carcinogenesis inrats.