IRON INTAKE AFFECTS LIPID-PEROXIDATION AND GLUTATHIONE-PEROXIDASE ACTIVITY OF DISTAL COLONIC MUCOSA

The purpose of this study was to examine the effect of low, adequate, and high dietary iron (Fe) levels on lipid peroxidation, glutathione S -transferase (GST) and glutathione peroxidase (GSH-Px) activities, and glutathione (GSH) concentrations in colon and liver. Male Sprague Daw ley rats were fed iron deficient (DFe; 14 mg Fe/kg diet; n=8), adequat e iron (AFe; 39 mg Fe/kg diet, n=8), or high iron (HFe; 454 mg Fe/kg d iet; n=8) diets for 3 weeks. Liver Fe concentrations were 26, 84, and 243 mu g/g wet weight, respectively, for rats fed DFe, AFe, and HFe di ets (p<0.0001). Lipid peroxidation was increased 70% in distal colonic mucosa of rats fed HFe diets compared to that of rats fed AFe and DFe diets (p<0.01), but lipid peroxidation was unaffected by diet in prox imal colon or liver. While distal colonic mucosal GSH-Px activity was lower in DFe rats (0.062 U/mg protein), than in AFe rats (0.091 U/mg p rotein), and HFe rats (0.089 U/mg protein) (p<0.05), iron intake had n o effect on GSH-Px activity in proximal colon or liver. The distal col on had higher GSH-Px activity than proximal colon (p<0.0001). GST acti vity in colon and liver, and hepatic GSH concentrations were not alter ed by dietary iron intakes. This Study suggests that distal and proxim al colonic mucosa may respond differently to changes in Fe status. (C) 1997 Elsevier Science Inc.