scholarly journals A validated method to assess glutathione peroxidase enzyme activity

2021 ◽  
Author(s):  
Mahmoud H. Hadwan ◽  
Ahmed Yasser Ahmed
Keyword(s):  
Glutathione Peroxidase ◽  
Peroxidase Activity ◽  
Comparison Method ◽  
Glutathione Peroxidase Activity ◽  
Altman Plot ◽  
Box Behnken Design ◽  
Plot Analysis ◽  
Peroxidase Enzyme ◽  
Matched Samples ◽  
Gpx Activity

Abstract This essay presents a reliable, effective and easy procedure for measuring glutathione peroxidase activity (Gpx). The enzyme samples were incubated with phosphate buffer, which included appropriate concentrations of glutathione and peroxide as substrates, to determine the Gpx activity. After a sufficient incubation time, the CUPRAC reagent (Cu(Nc) 2 2+ ) was added to stop the enzyme’s reaction. The unreacted substrates act to reduce Cu(II)-neocuproine complex (Cu(Nc) 2 2+ ) to strongly coloured Cu(I)-neocuproine complex (Cu(Nc) 2 + ) that was measured spectrophotometrically at 450 nm (CUPRAC method). The glutathione peroxidase activity was linked to a decrease in the absorbance of the coloured Cu(I)-neocuproine complex (Cu(Nc) 2 + ). The procedure uses the Box–Behnken design (BBD) to optimise the formation of the Cu(I)-neocuproine complex (Cu(Nc) 2 + ). The response surface methodology (RSM) is used to determine the accuracy of the method. This new protocol was confirmed by applying a Bland–Altman plot analysis of Gpx activity in matched samples using the Gpx-DTNB assay. The correlation coefficient between the two protocols was 0.9967. This means that the new protocol was very accurate and on par with the comparison method.

scholarly journals Effects of estrogens and androgens on erythrocyte antioxidant superoxide dismutase, catalase and glutathione peroxidase activities during the menstrual cycle

2000 ◽  
Vol 167 (3) ◽  
pp. 447-452 ◽  
Author(s):  
C Massafra ◽  
D Gioia ◽  
C De Felice ◽  
E Picciolini ◽  
V De Leo ◽  
...  
Keyword(s):  
Superoxide Dismutase ◽  
Menstrual Cycle ◽  
Glutathione Peroxidase ◽  
Peroxidase Activity ◽  
Free Testosterone ◽  
Cycle Phase ◽  
Activity Levels ◽  
Glutathione Peroxidase Activity ◽  
Antioxidant Enzyme System ◽  
Peroxidase Enzyme

The effects of physiological changes in estrogens and androgens on the erythrocyte antioxidant superoxide dismutase, catalase and glutathione peroxidase enzyme activities during the menstrual cycle were investigated in healthy eumenorrheic women. Blood samples were taken on alternate days from twelve normally cyclic women (age range: 20 to 27 years; mean age: 24.1 years) from the first day of one menstrual cycle until the first day of the subsequent one. Plasma was analyzed for FSH, LH, estradiol, progesterone, testosterone, free testosterone and androstenedione concentrations. Erythrocyte superoxide dismutase, catalase and glutathione peroxidase activities were evaluated on the same days and cycle length was standardized on the basis of the preovulatory estradiol peak. Significant cyclic phase-related changes were observed in glutathione peroxidase (P<0.05), with higher glutathione peroxidase activity levels from the late follicular to the early luteal phase compared with those found in the early follicular phase (P<0.001 and P<0.002 respectively). A significant positive correlation was observed between mean estradiol and glutathione peroxidase cycle-related variations (r=0.80, P<0.001), whereas no significant cycle phase-dependent changes were seen in superoxide dismutase and catalase. No effect of progesterone and androgens on the erythrocyte antioxidant enzyme system was documented. The findings indicate that physiological ovarian estradiol production during the menstrual cycle may have an important role in regulating erythrocyte glutathione peroxidase activity.

scholarly journals Low glutathione peroxidase activity in Gpx1knockout mice protects jejunum crypts from γ-irradiation damage

2000 ◽  
Vol 279 (2) ◽  
pp. G426-G436 ◽  
Author(s):  
R. Steven Esworthy ◽  
Jeffrey R. Mann ◽  
Mindy Sam ◽  
Fong-Fong Chu
Keyword(s):  
Gene Expression ◽  
Glutathione Peroxidase ◽  
Protective Effect ◽  
Peroxidase Activity ◽  
Irradiation Damage ◽  
Wild Type ◽  
Glutathione Peroxidase Activity ◽  
Γ Irradiation ◽  
Gpx Activity

Gpx1 knockout (KO) mice had a higher number of regenerating crypts in the jejunum than did Gpx2-KO or wild-type mice analyzed 4 days after ≥10 Gy γ-irradiation. Without γ-irradiation, glutathione peroxidase (GPX) activity in the jejunal and ileal epithelium of Gpx1-KO mice was <10 and ∼35%, respectively, of that of the wild-type mice. Four days after exposure to 11 Gy, GPX activity in wild-type and Gpx1-KO ileum was doubled and tripled, respectively. However, jejunal GPX activity was not changed. Thus the lack of GPX activity in the jejunum is associated with better regeneration of crypt epithelium after radiation. Gpx2 gene expression was solely responsible for the increase in GPX activity in the ileum, since radiation did not alter GPX activity in Gpx2-KO mice. The intestinal Gpx2mRNA levels of Gpx1-KO and wild-type mice increased up to 14- and 7-fold after radiation, respectively. Although the Gpx1-KO jejunum had higher levels of PGE2 than the wild-type jejunum after exposure to 0 or 15 Gy, these differences were not statistically significant. Thus whether GPX inhibits PG biosynthesis in vivo remains to be established. We can conclude that the Gpx2 gene compensates for the lack of Gpx1gene expression in the ileal epithelium. This may have abolished the protective effect in Gpx1-KO mice against the radiation damage in the ileum.

Selenium biofortified alfalfa hay fed in low quantities improves selenium status and glutathione peroxidase activity in transition dairy cows and their calves

2020 ◽  
Vol 87 (2) ◽  
pp. 184-190 ◽  
Author(s):  
Shana Jaaf ◽  
Brandon Batty ◽  
Angela Krueger ◽  
Charles T. Estill ◽  
Massimo Bionaz
Keyword(s):  
Glutathione Peroxidase ◽  
Dairy Cows ◽  
Peroxidase Activity ◽  
Post Partum ◽  
Selenium Status ◽  
Glutathione Peroxidase Activity ◽  
Dry Period ◽  
Alfalfa Hay ◽  
Gpx Activity ◽  
Modest Effect

AbstractThe hypothesis of the study was that feeding a relatively low amount of Se biofortified alfalfa hay during the dry period and early lactation would improve selenium status and glutathione peroxidase activity in dairy cows and their calves. Ten Jersey and 8 Holstein primiparous dairy cows were supplemented with Se biofortified (TRT; n = 9) or non-biofortified (CTR; n = 9) alfalfa hay at a rate of 1 kg/100 kg of BW mixed with the TMR from 40 d prior parturition to 2 weeks post-partum. Se concentration in whole blood, liver, milk, and colostrum, the transfer of Se to calves, and the glutathione peroxidase (GPx) activity were assessed. TRT had 2-fold larger (P < 0.05) Se in blood v. CTR that resulted in larger Se in liver and colostrum but not milk and larger GPx activity in plasma and erythrocytes but not in milk. Compared to CTR, calves from TRT had larger Se in blood but only a numerical (P = 0.09) larger GPx activity in plasma. A positive correlation was detected between Se in the blood and GPx activity in erythrocytes and plasma in cows. Our results demonstrated that feeding pregnant primiparous dairy cows with a relatively low amount of Se-biofortified alfalfa hay is an effective way to increase Se in the blood and liver, leading to greater antioxidant activity via GPx. The same treatment was effective in improving Se concentration in calves but had a modest effect on their GPx activity. Feeding Se biofortified hay increased Se concentration in colostrum but not in milk.

Low Selenium Status in the Elderly Influences Thyroid Hormones

1995 ◽  
Vol 89 (6) ◽  
pp. 637-642 ◽  
Author(s):  
Oliviero Olivieri ◽  
Domenico Girelli ◽  
Margherita Azzini ◽  
Anna Maria Stanzial ◽  
Carla Russo ◽  
...  
Keyword(s):  
Glutathione Peroxidase ◽  
Thyroid Hormones ◽  
Peroxidase Activity ◽  
Controlled Trial ◽  
The Elderly ◽  
Serum Selenium ◽  
Selenium Status ◽  
Glutathione Peroxidase Activity ◽  
Double Blind ◽  
Double Blind Placebo

1. Iodothyronine 5′-deiodinase, which is mainly responsible for peripheral triiodothyronine (T3) production, has recently been demonstrated to be a selenium-containing enzyme. In the elderly, reduced peripheral conversion of thyroxine (T4) to T3 and overt hypothyroidism are frequently observed. 2. We measured serum selenium and erythrocyte glutathione peroxidase (as indices of selenium status), thyroid hormones and thyroid-stimulating hormone in 109 healthy euthyroid subjects (52 women, 57 men), carefully selected to exclude abnormally low thyroid hormone levels induced by acute or chronic diseases or calorie restriction. The subjects were subdivided into three age groups. To avoid conditions of undernutrition or malnutrition, dietary records were obtained for a sample of 24 subjects, randomly selected and representative of the whole population for age and sex. 3. In order to properly assess the influence of selenium status on iodothyronine 5′-deiodinase type I activity, a double-blind placebo-controlled trial was also carried out on 36 elderly subjects, resident at a privately owned nursing home. 4. In the free-living population, a progressive reduction of the T3/T4 ratio (due to increased T4 levels) and of selenium and erythrocyte glutathione peroxidase activity was observed with advancing age. A highly significant linear correlation between T4, T3/T4 and selenium was observed in the population as a whole (for T4, R = −0.312, P < 0.002; for T3/T4 ratio, R = 0.32, P < 0.01) and in older subjects (for T4, R = −0.40, P < 0.05; for T3/T4 ratio, R = 0.54, P < 0.002). 5. The main result of the double-blind placebo-controlled trial was a significant improvement of selenium indices and a decrease in the T4 level in selenium-treated subjects; serum selenium, erythrocyte glutathione peroxidase activity and thyroid hormones did not change in placebo-treated subjects. 6. We concluded that selenium status influences thyroid hormones in the elderly, mainly modulating T4 levels.

scholarly journals Selenium levels and glutathione peroxidase activity in patients with ataxia-telangiectasia: association with oxidative stress and lipid status biomarkers

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Itana Gomes Alves Andrade ◽  
Fabíola Isabel Suano-Souza ◽  
Fernando Luiz Affonso Fonseca ◽  
Carolina Sanchez Aranda Lago ◽  
Roseli Oselka Saccardo Sarni
Keyword(s):  
Oxidative Stress ◽  
Glutathione Peroxidase ◽  
Peroxidase Activity ◽  
Oxidized Ldl ◽  
Reference Value ◽  
Glutathione Peroxidase Activity ◽  
Oxidative Stress Biomarkers ◽  
Apo B ◽  
Lipid Status ◽  
And Oxidative Stress

Abstract Introduction Ataxia-Telangiectasia (A-T) is a multi-system disorder that may be associated with endocrine changes, oxidative stress in addition to inflammation. Studies suggest that selenium is a trace element related to protection against damage caused by oxidative stress. Objective To describe the plasma levels of selenium and erythrocyte glutathione peroxidase activity in A-T patients and to relate them to oxidative stress and lipid status biomarkers. Methods This is a cross-sectional and controlled study evaluating 22 A-T patients (age median, 12.2 years old) matched by gender and age with 18 healthy controls. We evaluated: nutritional status, food intake, plasma selenium levels, erythrocyte glutathione peroxidase activity, lipid status, inflammation and oxidative stress biomarkers. Results Adequate levels of selenium were observed in 24/36 (66.7%) in this evaluated population. There was no statistically significant difference between the groups in selenium levels [47.6 μg/L (43.2–57.0) vs 54.6 (45.2–62.6) μg/dL, p = 0.242]. Nine of A-T patients (41%) had selenium levels below the reference value. The A-T group presented higher levels of LDL-c, non-HDL-c, oxidized LDL, Apo B, Apo-B/Apo-A-I1, LDL-c/HDL-c ratio, malondialdehyde [3.8 µg/L vs 2.8 µg/L, p = 0.029] and lower Apo-A-I1/HDL-c and glutathione peroxidase activity [7300 U/L vs 8686 U/L, p = 0.005]. Selenium levels were influenced, in both groups, independently, by the concentrations of oxidized LDL, malonaldehyde and non-HDL-c. The oxidized LDL (AUC = 0.849) and ALT (AUC = 0.854) were the variables that showed the greatest discriminatory power between groups. Conclusion In conclusion, we observed the presence of selenium below the reference value in nearly 40% and low GPx activity in A-T patients. There was a significant, inverse and independent association between selenium concentrations and oxidative stress biomarkers. Those data reinforce the importance of assessing the nutritional status of selenium in those patients.

scholarly journals The distribution, induction and isoenzyme profile of glutathione S-transferase and glutathione peroxidase in isolated rat liver parenchymal, Kupffer and endothelial cells

1989 ◽  
Vol 264 (3) ◽  
pp. 737-744 ◽  
Author(s):  
P Steinberg ◽  
H Schramm ◽  
L Schladt ◽  
L W Robertson ◽  
H Thomas ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Glutathione Peroxidase ◽  
Rat Liver ◽  
Peroxidase Activity ◽  
Cell Types ◽  
Transferase Activity ◽  
Glutathione Peroxidase Activity ◽  
Glutathione S Transferase ◽  
Liver Parenchymal ◽  
Parenchymal Cells

The distribution and inducibility of cytosolic glutathione S-transferase (EC 2.5.1.18) and glutathione peroxidase (EC 1.11.1.19) activities in rat liver parenchymal, Kupffer and endothelial cells were studied. In untreated rats glutathione S-transferase activity with 1-chloro-2,4-dinitrobenzene and 4-hydroxynon-2-trans-enal as substrates was 1.7-2.2-fold higher in parenchymal cells than in Kupffer and endothelial cells, whereas total, selenium-dependent and non-selenium-dependent glutathione peroxidase activities were similar in all three cell types. Glutathione S-transferase isoenzymes in parenchymal and non-parenchymal cells isolated from untreated rats were separated by chromatofocusing in an f.p.l.c. system: all glutathione S-transferase isoenzymes observed in the sinusoidal lining cells were also detected in the parenchymal cells, whereas Kupffer and endothelial cells lacked several glutathione S-transferase isoenzymes present in parenchymal cells. At 5 days after administration of Arocolor 1254 glutathione S-transferase activity was only enhanced in parenchymal cells; furthermore, selenium-dependent glutathione peroxidase activity decreased in parenchymal and non-parenchymal cells. At 13 days after a single injection of Aroclor 1254 a strong induction of glutathione S-transferase had taken place in all three cell types, whereas selenium-dependent glutathione peroxidase activity remained unchanged (endothelial cells) or was depressed (parenchymal and Kupffer cells). Hence these results clearly establish that glutathione S-transferase and glutathione peroxidase are differentially regulated in rat liver parenchymal as well as non-parenchymal cells. The presence of glutathione peroxidase and several glutathione S-transferase isoenzymes capable of detoxifying a variety of compounds in Kupffer and endothelial cells might be crucial to protect the liver from damage by potentially hepatotoxic substances.

Glutathione peroxidase activity in patients with renal disorders

2005 ◽  
Vol 9 (2) ◽  
pp. 127-131 ◽  
Author(s):  
Mohamed A. El-far ◽  
Mohamed A. Bakr ◽  
Sami E. Farahat ◽  
Elsaid A. Abd El-Fattah
Keyword(s):  
Glutathione Peroxidase ◽  
Peroxidase Activity ◽  
Glutathione Peroxidase Activity ◽  
Renal Disorders
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