ETHANOL EFFECTS ON LIPID-PEROXIDATION AND GLUTATHIONE-MEDIATED DEFENSE IN RAT SMALL-INTESTINE - ROLE OF DIETARY FATS

The effect of ethanol feeding for 5 weeks on lipid peroxidation status of small intestine was studied in rats maintained on either a rat pel let (RP) or a semisynthetic diet containing coconut oil (CCO), corn oi l (GO), or fish oil (FO). Highest rate of iron/ascorbate-induced lipid peroxidation was observed in intestinal mucosa of FO-fed rats, which was further elevated (p < 0.05) upon ethanol administration. Purified brush borders from all the ethanol-treated dietary groups were more su sceptible to iron-induced lipid peroxidation. Level of nonprotein thio ls was increased by ethanol feeding to rats given CO or FO. FO-fed rat s exhibited increased activities of glutathione reductase (GR), glutat hione-S-transferase (GST), and catalase (Cat). Glutathione peroxidase (GPx) was the lowest in the CCO group. Ethanol-treated FO group exhibi ted increased GST and GPx activities compared to controls, whereas in rats fed the RP or CO diet, ethanol feeding significantly decreased GS T activity. GR and Cat activities were not affected under these condit ions. Thus, ethanol exposes the small intestinal mucosa to oxidative s tress. The effects were more pronounced in rats fed n-3 fatty acid-ric h (FO) diet. The corresponding rise ih GPx and GST levels may reflect the adaptive changes in intestine. (C) 1998 Elsevier Science Inc.