Influence of melatonin on glutathione system in rats skeletal muscle under alloxan induced diabetes

Abstract

The aim was to determine the influence of melatonin on basal levels of glucose (BG), the levels of protein carbonyl content, HbA 1c and thiobarbituric acid reactive compounds (TBCRC), reduced glutathione (GSH), activities of glutathione reductase [EC 1.6.4.2] (GR), glutathione peroxidase [EC 1.11.1.9] (GPx), glucose-6-phosphate dehydrogenase [EC 1.1.1.49] (G-6-PhD) in the muscles of alloxan diabetic rats (DM1T). BG levels in blood of rats with DM1T increased on 139%, while in group of alloxan diabetic rats with impaired glucose tolerance (IGT)-were not differ from control. HbA 1c levels in the blood of animals with DM1T and IGT exceeded control by 219% and 123%, the level of protein carbonyl groups-by 76% and 36%, the level of TBCRC-by 58% and 36% respectively. Activities of GR, GPx, G-6-PhD and the level of GSH were decreased on 25%, 18%, 50% and 42% in rats with DM1T while in rats with IGT these indexes (besides GSH) were increased on 37%, 22%, 35% respectively than control. Melatonin lowered the BG level on 56% in DM1T rats in comparison to initial levels. It normalized activities of GR, GPx, G-6-PhD and lipid peroxidation, and protein carbonylation as well as hemoglobin glycosylation, so these indexes did not differ from control. Thus, melatonin has strong potential to regulate glucose homeostasis through enhanced glucose consumption, decreased oxidative stress by activation of the glutathione protection system.