Stimulation of chemically induced rectal carcinogenesis by chronic ethanol ingestion.
The effect of chronic ethanol administration on 1, 2-dimethylhydrazine-induced rectal carcinogenesis was investigated in 32 paired male Sprague-Dawley rats fed a nutritionally-adequate liquid diet containing 36% of the total calories as either ethanol or isocaloric carbohydrates. Chronic ethanol ingestion increased the total number of rectal tumors significantly (17 vs 6; P less than 0.02), whereas no cocarcinogenic effect of ethanol was observed in other parts of the intestine. Alcohol did not influence tumor size or histopathology. A 47% increase in the activity of mucosal alcohol dehydrogenase in the distal colorectal region was found between chronically-ethanol-fed rats and pair-fed controls (0.241 +/- 0.019 vs 0.164 +/- 0.020 mumol/mg of protein/hr; P less than 0.01). This could in part explain the cocarcinogenic effect of alcohol in this tissue. Faecal bile acids, however, do not play a role as promotors of rectal carcinogenesis under the present experimental conditions. The results give experimental support to the epidemiologic findings of an increased incidence of rectal cancer in the alcoholic.
D000230:Adenocarcinoma / Q000139:chemically induced / Q000556:secondary; D000429:Alcohol Oxidoreductases / Q000378:metabolism; D000818:Animals; D001647:Bile Acids and Salts / Q000378:metabolism; D003106:Colon / Q000201:enzymology; D004127:Dimethylhydrazines; D000431:Ethanol / Q000009:adverse effects*; D007414:Intestinal Neoplasms / Q000139:chemically induced; D007417:Intestinal Polyps / Q000139:chemically induced / Q000556:secondary; D008099:Liver / Q000201:enzymology; D008297:Male; D009092:Mucous Membrane / Q000201:enzymology; D051381:Rats; D011919:Rats, Inbred Strains; D012004:Rectal Neoplasms / Q000139:chemically induced*; D012007:Rectum / Q000201:enzymology
D001647:Bile Acids and Salts; D004127:Dimethylhydrazines; D000431:Ethanol; D000429:Alcohol Oxidoreductases