Effects of chronic ethanol consumption on carcinogen activating and detoxifying systems in rat upper alimentary tract tissue.

The effect of chronic ethanol consumption on enzyme systems directly involved in carcinogen activation and detoxification were studied in rat upper alimentary tract tissue. Microsomal cytochrome P-450 (P-450) levels and glutathione levels as well as glutathione transferase and UDP-glucuronic acid transferase (UDPGT) activities were measured in mucosa scraped from esophagus, forestomach and glandular stomach of rats which had been pair-fed ethanol or dextrimaltose-containing diets. Esophageal and forestomach P-450 levels were increased in the ethanol-fed rats. The ethanol diet also produced a small but significant increase in esophageal glutathione transferase levels. Glutathione levels and UDPGT activity were unaffected. Since P-450 is directly involved in the activation of many chemical carcinogens, these results are consistent with the hypothesis that the increase in upper alimentary tract cancer risk associated with alcohol abuse is due, at least in part, to ethanol's altering the balance between carcinogen activation and detoxification.