Selenium – Glutathione Peroxidase Relation in Erythrocytes With G-6-PDH Deficiency and the Gp Activity Deviation During Oxidation by Selenium. Mini-Review

Abstract

Selenium status and glutathione peroxidase (GP) activity were investigated in patients with normal and glucose-6-phosphate dehydrogenase (G-6-PDH) deficient erythrocytes among Azerbaijani population. It has been shown that the content of Se in G-6-PDH-deficient erythrocytes is a little (≈16%) different from the norm, while GP activity of in them is substantially lower (≈ 50%). The low activity of GP probably is due to decreased production of GSH, the basic substrate for GP, in G-6-PDH-deficient erythrocytes. Addition of GSH precursor (N-acetylcysteine) to the incubation medium increases the GP activity, suggesting that the low level of GP activity is possibly connected with low level of GSH. G-6-PDH-deficient erythrocytes demonstrate significantly greater susceptibility to oxidative stress than normal ones when exposed to ultraviolet radiation of the small (7 kJ/m 2) and moderate (15 kJ/m 2) doses, and to high tension electric field (HTEF ≈ 60 kV/m × 5 hours). In particular, the accumulation of lipid peroxidation products (malonic dialdehyde) under visible UV irradiation in G-6-PDH-deficient erythrocytes is ≈50-80% higher, than in the control. Nevertheless, in G-6-PDH-deficient erythrocytes HTEF have no significant effect on the accumulation of malonic dialdehyde, though the GP and catalase activity are falling faster than normal, and have initially lower level.

Increased Morbidity and Its Possible Link to Impaired Selenium Status

“…This is further evidence that Hb enzyme activity does not always adequately reflect selenium status [43,44]. Regarding the effect of selenium on the health of pregnant women, it can be noted that pregnancy pathologies such as threatened termination, intrauterine fetal delay are accompanied by a decrease in selenium levels and Hb activity in serum, erythrocytes with an increase in lipid peroxidation (LPO) of erythrocytes [43,44]. Selenium deficiency has been found to impair the regulation of nutrient transport through the placenta [49,50].…”

“…At the same time, the frequency of selenium presence in Hb for humans in norm according to one data is 1: 225 [80], according to other data Se: Hb1: 300 [43,44].…”

“…Selenium is incorporated into hemoglobin by sulfur substitution predominantly in cysteine residues at the βCys93 position. Considering that it will affect the electronic environment of proximal histidine, which is in close proximity to heme, one can assume that it will enhance its antioxidant protection [43][44][45].…”

“…At the same time, the Hb activity in erythrocytes is weakly altered even in the third trimester of pregnancy. This is further evidence that Hb enzyme activity does not always adequately reflect selenium status [43,44]. Regarding the effect of selenium on the health of pregnant women, it can be noted that pregnancy pathologies such as threatened termination, intrauterine fetal delay are accompanied by a decrease in selenium levels and Hb activity in serum, erythrocytes with an increase in lipid peroxidation (LPO) of erythrocytes [43,44].…”