Effect of Sodium Selenite on Lipid Peroxidation Processes and Concentration of Sex Hormones during Intensive Physical Exercise

The expression of selenoproteins, which in turn depends on the provision of tissues with exogenous selenium supplied with food, is important in the functioning of the antioxidant system. There is data on an increase in the intensity of free radical processes with a deficiency of selenium in the organism. The aim of this study is to establish the effect of sodium selenite on lipid peroxidation processes and concentration of sex hormones during intensive physical exercise. The study was carried out on 60 male rats that were divided into four groups (n = 15). The first group included the control animals. The second and third groups were experimental (animals of these groups swam with the same load (10% of the body weight) but differed in the intensity of training). Animals of the fourth group swam with the load of 10% and received sodium selenite (Na₂SeO₃) at a dose of 30 μg/day/kg of body weight. After completing the experiment, the blood was taken from animals to study biochemical indices (total testosterone, free testosterone, thyroxine, triiodothyronine, malondialdehyde, glutathione, activity of glutathione peroxidase and glutathione reductase). During the experiment, it was established that intensive physical exercise causes a decrease in concentration of the studied hormones in the blood serum and contribute to the intensification of free radical oxidation and processes of lipid peroxidation, which is evidenced by an increase in the content of malonic dialdehyde in erythrocytes and a change in the parameters of the glutathione antioxidant system. The administration of sodium selenite at a dose of 30 μg/day/kg of body weight contributes to the restoration of the level of sex steroids, without affecting the level of thyroid hormones and contributes to a decrease in the level of malonic dialdehyde and an increase in the concentration of glutathione as compared with the third group. The activity of glutathione-dependent enzymes under the effect of sodium selenite also increases. Thus, high intensity physical exercise contributes to an increase in the content of lipid peroxidation products in the blood, inhibition of antioxidant function, and a decrease in the level of thyroid and sex hormones. The administration of sodium selenite contributes to a decrease in free radical processes and an increase in the concentration of sex hormones but has no effect on the content of thyroid hormones as compared with the group of rats experiencing intensive physical exercise.