Comparison of the effects of zinc alone and zinc associated with selenium and vitamin E on insulin sensitivity and oxidative stress in high-fructose-fed rats.
OBJECTIVE
In the present study, we investigated the effect of an association of micronutrients (zinc (Zn), selenium (Se) and vitamin E (vit E)) on insulin activity and antioxidant status in an animal model of insulin resistance, the high-fructose-fed rat.


METHODS
Five experimental groups were compared: a control group (C) receiving a standard diet, a high-fructose-fed group (F) where 58% of the diet carbohydrate was fructose, a high-fructose-fed group supplemented with Zn alone (FZn group), a high-fructose-fed group supplemented micronutrients (Zn, Se and vit E) (FMicro group). A fifth group consumed a high-fructose diet and received metformin in the drinking water (200mg/day/rat) (FMet group). Insulin sensitivity was measured using the euglycemic hyperinsulinic glucose clamp technique. Metabolic parameters, trace elements and antioxidant parameters were measured in blood samples from all groups.


RESULTS
High-fructose-fed rats were resistant to insulin as indicated by the lower glucose infusion rate. The insulin sensitivity of FZn, FMicro and FMet groups was higher than that of F group, with the highest insulin sensitivity for the FMicro group. No statistically significant difference in glycemia between the groups was observed. The ratio of reduced to oxidized glutathione was higher in FZn and FMicro groups than in all other groups, as a consequence of decreased oxidized glutathione.


CONCLUSIONS
Our results provide direct evidence that micronutrients have a beneficial effect on insulin sensitivity and some components of the antioxidant defense system in an animal model of insulin resistance.
Faure
Patrice
P
Laboratoire HP2, Hypoxie Physio-Pathologie Respiratoire et Cardiovasculaire, Inserm ERI 0017, Faculté de Médecine-Pharmacie, BP 217, 38043 Grenoble cedex 9, France. PFaure@chu-grenoble.fr
Barclay
Denis
D
Joyeux-Faure
Marie
M
Halimi
Serge
S
D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D004032:Diet; D004040:Dietary Carbohydrates; D005632:Fructose / Q000008:administration & dosage* / Q000378:metabolism; D015309:Glucose Clamp Technique; D007004:Hypoglycemic Agents / Q000378:metabolism; D007328:Insulin / Q000378:metabolism*; D007333:Insulin Resistance; D008055:Lipids / Q000737:chemistry; D008297:Male; D008687:Metformin / Q000378:metabolism; D018977:Micronutrients; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D011506:Proteins / Q000737:chemistry; D051381:Rats; D017208:Rats, Wistar; D012643:Selenium / Q000378:metabolism*; D014810:Vitamin E / Q000378:metabolism*; D015032:Zinc / Q000378:metabolism*
D000975:Antioxidants; D004040:Dietary Carbohydrates; D007004:Hypoglycemic Agents; D007328:Insulin; D008055:Lipids; D018977:Micronutrients; D011506:Proteins; D014810:Vitamin E; D005632:Fructose; D008687:Metformin; D012643:Selenium; D015032:Zinc