TI:  Effects of Ethanol, Potassium Metabisulfite, Formaldehyde 
     and Hydrogen Peroxide on Gastric Carcinogenesis in Rats 
     After Initiation with N-Methyl-N'-Nitro-N-Nitrosoguanidine

DT:  October 3, 1985

AU:  M. Takahashi, R. Hasegawa, F. Furukawa, K. Toyoda, H. Sato,
     Y. Hayashi

SO:  Jpn. J. Cancer Res. (Gann), 77, 118-124; February, 1986

AB:  Ethanol, potassium metabisulfite, formaldehyde and hydrogen 
     peroxide were tested for tumor-promoting activity in a two-
     stage stomach carcinogenesis experiment.  Male outbred 
     Wistar rats were given N-methyl-N'-nitro-N-nitrosoguanidine 
     (MNNG) in the drinking water (100 mg/liter) and a diet 
     supplemented with 10% sodium chloride for 8 weeks.  
     Thereafter, they were maintained on drinking water 
     containing either 10% ethanol, 1% potassium metabisulfite, 
     0.5% formalin (formaldehyde) or 1% hydrogen peroxide for 32 
     weeks and then sacrificed for necropsy and histological 
     examination.  In the pylorus of the glandular stomach, 
     potassium metabisulfite and formaldehyde significantly 
     increased the incidence of adenocarcinoma after initiation 
     with MNNG and sodium chloride.  Hydrogen peroxide did not 
     enhance the tumor yield, and ethanol showed a tendency to 
     decrease neoplastic development.  In the fore-stomach the 
     incidence of squamous cell papilloma was significantly 
     increased in the groups given hydrogen peroxide or 
     formaldehyde, irrespective of prior initiation.  Duodenal 
     adenocarcinoma was induced by the initiation alone (10%) and 
     the incidence was not affected by the subsequent treatments.  
     The results indicate that potassium metabisulfite and 
     formaldehyde both exert tumor-promoting activity in the rat 
     glandular stomach.