Manganese status, gut endogenous losses of manganese, and antioxidant enzyme activity in rats fed varying levels of manganese and fat.
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概要
We hypothesized that manganese deficient animals fed high vs moderate levels of polyunsaturated fat would either manifest evidence of increased oxidative stress or would experience compensatory changes in antioxidant enzymes and/or shifts in manganese utilization that result in decreased endogenous gut manganese losses. Rats (females in Study 1, males in Study 2, n = 8/treatment) were fed diets that contained 5 or 20% corn oil by weight and either 0.01 or 1.5 mumol manganese/g diet. In study 2, 54Mn complexed to albumin was injected into the portal vein to assess gut endogenous losses of manganese. The manganese deficient rats: 1. Had 30-50% lower liver, tibia, kidney, spleen, and pancreas manganese concentrations than manganese adequate rats; 2. Conserved manganese through approximately 70-fold reductions in endogenous fecal losses of manganese; 3. Had lower heart manganese superoxide dismutase (MnSOD) activity; and 4. Experienced only two minor compensatory changes in the activity of copper-zinc superoxide dismutase (CuZnSOD) and catalase. Gut endogenous losses of manganese tended to account for a smaller proportion of absorbed manganese in rats fed high-fat diets; otherwise fat intake had few effects on tissue manganese concentrations.