The glutathione system state in rats exposed to ethanol intoxication, its combination with caffeine and modified photoperiod

Objective. To study the content of reduced glutathione (GSH), activities of glutathione peroxidase (GP) and glutathione-S-transferase enzymes (GST) in blood and liver of rats exposed to subacute alcohol intoxication, its combination with caffeine intake or constant light exposure, and the possibility of their correction with melatonin.Materials and methods. Experiments were performed on 42 male rats weighing 180-200 g kept under standard conditions of the vivarium and artificial equinox. Alcohol intoxication was induced by intragastric administration 40 % ethanol at a dose of 7 ml/kg of body weight for 7 days. Caffeine was administered by gavage at a dose of 30 mg/kg of body weight.Results. Ethanol poisoning and its combination with caffeine intake or exposure to constant light resulted in a decrease in GSH level and GP activity in RBCs and liver, besides the combination of ethanol+light resulted in more pronounced depletion of the parameters. The combination of ethanol with caffeine resulted in less reduction of GSH level in the blood (by 25%) but more depletion of GSH in the liver (by 45% vs. control) than in ethanol-treated rats. There was an elevation of GST activity in the liver of all groups of alcoholized animals. Administration of 5 mg/kg melatonin for 7 days limited depletion in GSH and prevented the changes in GP and GST activities in the blood and liver of all groups of animals.Conclusions. Melatonin administration prevented ethanol-induced toxicity in rats exposed to ethanol and its combination with caffeine or constant light for 7 days by limiting the depletion in GSH and preventing the changes in GP and GST activities in the blood and liver of all groups of animals.