High vitamin E amount leads to a modification of zinc and copper tissue distribution in high fructose-fed rats exhibiting an insulin resistance

Aim: We have previously observed that high amounts of vitamin E lead to an improvement of insulin sensitivity in high fructose-fed rats. The aim of this work was to try out the effect of this diet on copper and zinc distribution in insulin-sensitive tissues such as muscle and liver. Methods: The rats (post weaning, 50 g) were divided into 3 groups: the control group (C, n = 16) which received a purified diet containing 60 g/100 g carbohydrates, the high fructose-fed group (FT, n = 16) fed a diet in which 56.8% of the carbohydrates were fructose, and a high fructose and vitamin E-fed group (FVE, n = 16) fed the FT diet supplemented with 3.4 g/kg diet vitamin E (vs 0.17 g/kg in C and FT groups). The duration of the treatment was 6 weeks. Insulin sensitivity was determined in half of the rats in each group using the euglycemic hyperinsulinic glucose clamp technique. The remaining rats were investigated for metabolic and free radical parameters, and for plasma, liver, and muscle (soleus muscle) copper and zinc concentrations. Results: The group FT had a significantly lower insulin sensitivity than the C group. The group FVE exhibited a higher insulin sensitivity than the FT group FT. Muscle zinc was significantly lower in groups FT and FVE than in the group C. Liver zinc and copper were lower in group FT than in group C and were increased in group FVE to become close to the values of the group C. In comparison with group FT, Cu-Zn-SOD activity was also improved in group FVE. Conclusion: Therefore, the question arises as to whether the effect of vitamin E on liver trace elements was linked to its effect on insulin activity.