Mean Glutathione Peroxidase Activity Research Articles

Glutathione as an antioxidant marker: determination of glutathione concentration in the breast muscles and liver of broilers supplemented with different selenium sources

The aim of the study was to determine the influence of different selenium sources on antioxidant properties. The glutathione (GSH) concentration and glutathione peroxidase (GPx) activity were measured in the breast muscles and liver of 60 one-day-old broiler chickens. Another goal was to compare these indices with the weights of individual tissues and the live weight of broilers. The broilers were divided into 4 groups according to the selenium source: group 1 (control), group 2 (selenized yeast), group 3 (selenomethionine), group 4 (sodium selenite). Treatment groups were supplemented with 0.2 mg of additional selenium/kg. No significant changes in the hepatic GSH concentrations (P> 0.05) were found in the experimental groups compared to control. Significantly higher GSH concentration (P< 0.05) was found in breast muscles of broilers in group 4 (sodium selenite) compared to control. However, no positive effect of selenium supplementation in the form of sodium selenite was observed. The differences in the GPx activity in breast muscles and liver between the experimental groups and the control group were not significant (P> 0.05). No significant differences were recorded in the experimental groups compared to control in relation to the GSH concentration and GPx activity measured in the tissues. A significantly positive correlation was noted between mean GPx activity in breast muscle and breast muscle weight (P< 0.01; r = 0.3790) and live weight (P< 0.05; r = 0.2690). Although changes in the GSH concentration and GPx activity were recorded in some experimental groups, the selected dose of additional selenium appeared to be too low to affect these concentrations and the antioxidant defence system.

Evaluation of oxaliplatin-induced pulmonary toxicity in rats.

IntroductionThe mechanism of oxaliplatin (OXA) induced pulmonary toxicity is not fully understood.Aim of the studyThe present study was designed to investigate the pulmonary toxicity of OXA that has been reported in previous studies. Study design: animal experiments.Material and methodsA total of 40 female Wistar rats were divided into 5 groups. In group 1, 5% glucose was injected intra-peritoneally; then the rats were sacrificed on day 14. OXA was administered in groups 2, 3, 4, and 5; then the animals were sacrificed on day 7 in group 2, day 14 in group 3, day 28 in group 4 and day 48 in group 5. The groups were further categorized as short-term administration and long-term administration groups. Furthermore, tissue glutathione peroxidase (GPX) activity was measured in all rats.ResultsThe mean GPX activities were 0.66 U/mg in the sham group, 0.74 U/mg in the short-term groups, and 0.74 U/mg in the long-term groups. We found that long-term OXA administration causes pulmonary toxicity resulting in increased intra-alveolar/interstitial macrophages and interstitial pneumonia. Similarly, we found reduced and permanent tissue GPX activity in rats that received OXA in higher doses and for a long term.ConclusionsLong-term OXA therapy causes toxic changes in the lung tissue.

Determination of antioxidant indices in dairy cows during the periparturient period

The aim of the present study was to evaluate indicators of antioxidant status – glutathione peroxidase (GPx); superoxide dismutase (SOD); total antioxidant status (TAS); vitamins A, E and beta carotene in 10 dairy cows of the Holstein breed from 15-20 days ante partum (a.p.) to 25–30 days post partum (p.p.). Blood samples were collected 5 × during this period: 15–20 days a.p., 1–3 days a.p., 2–3 days p.p., 10–15 days p.p. and 25–30 days p.p. The mean GPx activity was significantly (P = 0.013) lower in the 10–15 days p.p. compared to 15–20 days a.p. (P < 0.05) and 1–3 days a.p. (P < 0.01). The increase of SOD values was monitored throughout the whole experiment. The mean TAS concentration was significantly (P < 0.01) decreased 2–3 days p.p. compared to 25–30 days p.p. A significantly lower mean concentration of vitamin A was also found 2–3 days p.p. compared to the concentration 15–20 days a.p. (P < 0.05) and 25–30 days p.p. (P < 0.001). A significant (P < 0.001) decrease in vitamin E concentration was recorded in cows 2–3 days p.p. compared to cows 15–20 days a.p. and 25–30 days p.p. The mean concentration of beta carotene was also decreased immediately after calving. Significant changes in the concentration of antioxidant parameters during the periparturient period indicate the occurrence of oxidative stress in dairy cows which can contribute to increased incidence of metabolic diseases.

Serum Selenium Concentration in Cervical Cancer Patients: Preliminary Study and Literature Review

Objective: To analyze the role of selenium and glutathione peroxidase (GPx) in cervical cancer. Methods: Serum selenium concentrations and GPx activities of 19 women with cervical cancer along with their healthy counterparts (control group) were obtained. Selenium concentration were measured fluorometrically and GPx activities were measured spectrophotometrically based on the quantity of NADPH used in the reduction of glutathione. Results: The mean of serum selenium concentrations in cervical cancer group was significantly lower than that in the control group, 67.24±15 ng/mL and 77.05±12 ng/mL (p=0.03), respectively. The mean GPx activity in the cervical cancer group was also significantly lower than that in the control group, 128.18±38 ∆mmol NADPH/min/L and 148.9±23 ∆mmol NADPH/min/L (p=0.04), respectively. Multivariate analysis in the cervical cancer patients showed that the Federation Internationale de Gynecologie et d’Obstetrique (FIGO) staging score (early vs. advanced) was inversely correlated with serum selenium concentration (p=0.027). Conclusions: Serum selenium concentration and GPx activity was significantly lower in the cervical cancer patients. Our results demonstrate that selenium and GPx activity may have an important role in the carcinogenesis of cervical cancer. Keywords: Cervical cancer, glutathione peroxidase activity, selenium DOI: 10.15850/ijihs.v4n2.833

Tumor necrosis factor‐α supression rescues glutathione peroxidase activity in kidney of insulin resistant rats (1134.12)

The interactions between reactive oxygen species (ROS) production and kidney nephropathy in metabolic syndrome are not well described. This study assessed the effects of blocking 1) renin‐angiotensin system (RAS), 2) tumor necrosis factor‐alpha (TNFα)‐mediated inflammation, 3) and non‐RAS‐mediated hypertension on the activity of the antioxidant enzymes, glutathione peroxidase (GPx), catalase (CAT), and superoxide dismutase (SOD) in the kidney of insulin resistant (IR), Otsuka‐Long‐Evans‐Tokushima‐Fatty (OLETF) rats. Lean and obese rats (n = 5‐7/group) were randomly assigned to the following groups: 1) untreated Long‐Evans‐Tokushima‐Otsuka (LETO) (lean, strain control ), 2) untreated OLETF, 3) OLETF + angiotensin receptor blocker (ARB) (10 mg olmesartan/kg/d x 10 wk), 4) OLETF + TNFα blocker (ETAN) (1.25 mg entanercept/kg/d x 10 wk), 5) OLETF + calcium channel blocker (CCB) (3 mg amlodipine/kg/d x 10 wk), and 6) OLETF + ARB+ ETAN (COMBO) (same doses x 10 wk). OLETF exhibited a 23% decrease (41 ± 4 vs. 32 ± 3 nmol/min/ml) in mean GPx activity. TNFα blockade completely recovered the IR‐associated decrease in GPx activity (45 ± 4 nmol/min/ml) demonstrating that TNFα contributes to the dysregulation of antioxidant enzymes in the IR kidney. Catalase and SOD activities, while elevated, were not different among groups suggesting that the dysregulation of antioxidant enzymes is selective during IR conditions.Grant Funding Source: APS Teacher Researcher

Angiotensin II and mineralocorticoid receptor antagonism decrease cardiac nitrotyrosine content and recover glutathione peroxidase activity in Angiotensin II‐infused rats (856.10)

Angiotensin II (Ang II) and aldosterone (aldo) contribute to cardiovascular damage via oxidative stress, but their respective contributions remain elusive. To independently assess the contributions of Ang II and aldo during Ang II‐dependent hypertension, five groups of Sprague Dawley rats (n =11‐14/group) were studied: 1) Control, 2) Ang II infused (80 ng/min x 28d), 3) Ang II + angiotensin receptor blocker (ARB; 10 mg losartan/kg/d x 21d), 4) Ang II + mineralocorticoid receptor antagonist (Epl; 100 mg eplerenone/d x 21d), and 5) Ang II + ARB + Epl (Combo). ARB and Combo reduced the 65% Ang II‐induced increase in systolic blood pressure (SBP), but Epl had no effect. Epl exacerbated the increase in plasma and heart aldo while ARB reduced both. Ang II increased relative heart mass 19% and heart cardiotrophin‐1 content 57%. All treatments prevented these increases. Ang II reduced mean glutathione peroxidase activity 29%, while ARB and Combo recovered levels beyond Control by 25 and 28%, respectively. Ang II also increased superoxide dismutase (SOD) activity 20% whereas all treatments reduced SOD. Ang II increased mean heart nitrotyrosine (NT) content 3‐fold and mean 4‐hydroxynonenal (HNE) content 26%. All treatments improved NT, but Epl had no effect on HNE levels. Despite the inability to reduce SBP, chronic MR blockade prevented oxidative stress suggesting aldo as a therapeutic target for AT1‐mediated oxidative damage.Grant Funding Source: Supported in parts by: NHLBI K02HL103787/R01HL091767, NIH NIMHD T37MD001480, NIH

Liver lipid peroxidation and antioxidant capacity in cerulein-induced acute pancreatitis

The aim of this study was to evaluate the role of oxidative damage in pancreatitis-induced hepatic injury. Thirty-five rats were divided into five groups (each of 7 rats): control, cerulein (100 microg/kg body weight), cerulein and pentoxifylline (12 mg/kg body weight), cerulein plus L-NAME (10 mg/kg body weight) and cerulein plus L-arginine (160 mg/kg body weight). The degree of hepatic cell degeneration differed significantly between groups. Mean malondialdehyde levels were 7.00 +/- 2.29, 20.89 +/- 10.13, 11.52 +/- 4.60, 18.69 +/- 8.56, and 8.58 +/- 3.68 nmol/mg protein for the control, cerulein, pentoxifylline, L-NAME, and L-arginine groups, respectively. Mean catalase activity was 3.20 +/- 0.83, 1.09 +/- 0.35, 2.05 +/- 0.91, 1.70 +/- 0.60, and 2.85 +/- 0.47 U/mg protein for the control, cerulein, pentoxifylline, L-NAME, and L-arginine groups, respectively, and mean glutathione peroxidase activity was 0.72 +/- 0.25, 0.33 +/- 0.09, 0.37 +/- 0.04, 0.34 +/- 0.07 and 0.42 +/- 0.1 U/mg protein for the control, cerulein, pentoxifylline, L-NAME, and L-arginine groups, respectively. Cerulein-induced liver damage was accompanied by a significant increase in tissue malondialdehyde levels (P < 0.05) and a significant decrease in catalase (P < 0.05) and GPx activities (P < 0.05). L-arginine and pentoxifylline, but not L-NAME, protected against this damage. Oxidative injury plays an important role not only in the pathogenesis of AP but also in pancreatitis-induced hepatic damage.

Glutathione peroxidase (GPX) activity in blood of ewes on farms in different scrapie categories in Iceland

BackgroundPreliminary studies indicated decreased glutathione peroxidase (GPX) activity in blood of ewes on scrapie-afflicted farms. Other studies have shown decreased GPX activity in brain of prion-infected mice and in prion-infected cells in vitro. The aim of this study was to examine the GPX activity in blood as well as the distribution of GPX-activity levels from ewes on farms in scrapie-afflicted areas in Iceland.MethodsBlood samples were collected from 635 ewes (non-pregnant [n = 297] and pregnant [n = 338]) on 40 farms in scrapie-afflicted areas during the years 2001–2005, for analysis of GPX activity. The farms were divided into three categories: 1. Scrapie-free farms (n = 14); 2. Scrapie-prone farms (earlier scrapie-afflicted, restocked farms) (n = 12); 3. Scrapie-afflicted farms (n = 14). For comparison, 121 blood samples were also collected from non-pregnant ewes on one farm (farm A) in a scrapie-free area (scrapie never registered). Chi-square test was used to test for normal distribution of GPX-results, and Kruskal-Wallis test to compare GPX-results between categories.ResultsThe GPX-results appeared to be biphasically distributed in ewes in all three scrapie categories and on farm A. The presumptive breaking point was about 300 units g Hb-1. About 30–50% of the GPX-results from ewes in all three scrapie categories were below 300 units g Hb-1 but only about 13% of the GPX-results from ewes on farm A. The mean GPX activity was highest on farm A, and was significantly lower on scrapie-prone farms than on scrapie-free or scrapie-afflicted farms (non-pregnant and pregnant ewes: P < 0.005, respectively; non-pregnant and pregnant ewes combined: P < 0.0005).Conclusions1) the distribution of GPX-results in blood of Icelandic ewes apparently has a biphasic character; 2) the GPX-results were higher in ewes on one farm in a scrapie-free area than in ewes on farms in the scrapie-afflicted areas; 3) GPX-activity levels were significantly lowest on earlier scrapie-afflicted, restocked farms, which might have a bearing on the recurrence of sporadic scrapie on these farms; 4) further study on the possible role of GPX activity in the occurrence of scrapie in Iceland is warranted.

Glutathione level after long-term occupational elemental mercury exposure

Many in vitro and in vivo studies have elucidated the interaction of inorganic mercury (Hg) and glutathione. However, human studies are limited. In this study, we investigated the potential effects of remote long-term intermittent occupational elemental Hg vapour (Hg degrees ) exposure on erythrocyte glutathione levels and some antioxidative enzyme activities in ex-mercury miners in the period after exposure. The study included 49 ex-mercury miners divided into subgroups of 28 still active, Hg degrees -not-exposed miners and 21 elderly retired miners, and 41 controls, age-matched to the miners subgroup. The control workers were taken from "mercury-free works". Reduced glutathione (GSH) and oxidized disulphide glutathione (GSSG) concentrations in haemolysed erythrocytes were determined by capillary electrophoresis, while total glutathione (total GSH) and the GSH/GSSG ratio were calculated from the determined values. Catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) activities in erythrocytes were measured using commercially available reagent kits, while urine Hg (U-Hg) concentrations were determined by cold vapour atomic absorption (CVAAS). No correlation of present U-Hg levels, GSH, GSSG, and antioxidative enzymes with remote occupational biological exposure indices were found. The mean CAT activity in miners and retired miners was significantly higher (p<0.05) than in the controls. No differences in mean GPx activity among the three groups were found, whereas the mean GR activity was significantly higher (p<0.05) in miners than in retired miners. The mean concentrations of GSH (mmol/g Hb) in miners (13.03+/-3.71) were significantly higher (p<0.05) than in the control group (11.68+/-2.66). No differences in mean total GSH, GSSG levels, and GSH/GSSG ratio between miners and controls were found. A positive correlation between GSSG and present U-Hg excretion (r=0.41, p=0.001) in the whole group of ex-mercury miners was observed. The significantly lower GSH level (p<0.05) determined in the group of retired miners (9.64+/-1.45) seems to be age-related (r= -0.39, p=0.001). Thus, the moderate but significantly increased GSH level, GR and CAT activity in erythrocytes in the subgroup of miners observed in the period after exposure to Hg degrees could be an inductive and additive response to maintain the balance between GSH and antioxidative enzymes in interaction with the Hg body burden accumulated during remote occupational exposure, which does not represent a severely increased oxidative stress.

Selenium Supplementation and Blood Rheological Improvement in Japanese Adults

In order to study the prevention effect of selenium in the development of cardiovascular disease, we investigated the effects of selenium supplementation on the blood rheological properties. Eleven healthy adults were administered with 200 microg of selenium in the form of selenium yeast per day for 1 wk. Before and after the supplementation, serum selenium concentration, glutathione peroxidase (GPx) activity, biochemical indices, and the blood fluidity of the subjects were measured. The blood fluidity was measured using a (microchannel array flow analyzer) by the passage time of 100 microL of heparinized whole blood through the microchannel array. The selenium supplementation significantly (p = 0.001) shortened the mean blood passage time from 44.0 +/- 5.7 to 37.5 +/- 2.8 s. Serum selenium concentration significantly (p = 0.008) increased from 109.8 +/- 10.2 to 124.5 +/- 16.7 microg/L. Meanwhile, the GPx activity did not increased significantly (p = 0.058). The mean GPx activity of the subjects before supplementation was 171.0 +/- 16.1 Deltammol NADPH/min/L and 180.9 +/- 17.8 Deltammol NADPH/min/L after supplementation. Factor analysis of the passage time and biochemical indices of the subjects showed that blood fluidity improvement was related to the metabolic modification of lipoproteins during the selenium supplementation. These results showed that selenium supplementation improved the blood fluidity, without increasing the GPx activity of the subjects.

Determination of glutathione peroxidase and superoxide dismutase-like activities in equine spermatozoa, seminal plasma, and reproductive tissues

To determine glutathione peroxidase (GPX) and superoxide dismutase (SOD)-like activities in spermatozoa, seminal plasma, and reproductive tissues (ie, testis, epididymis, bulbourethral gland, prostate, vesicular gland, and ampulla) in horses. Seminal plasma from 17 stallions, spermatozoa from 5 stallions, and reproductive tissues from 3 stallions. Activity of GPX was determined by use of assays measuring oxidation of NADPH in the presence of exogenous glutathione, cumene hydroperoxide, and glutathione reductase. Activity of SOD-like enzymes was determined by use of the nitroblue tetrazolium assay. Mean GPX and SOD-like activities in seminal plasma were 1.3 +/- 0.1 nmol of NADPH oxidized/min/mg of protein and 29.2 +/- 6.6 U/mg of protein, respectively. Mean GPX activities in spermatozoa separated from seminal plasma by centrifugation and via Percoll gradient were 2.2 +/- 0.3 nmol and 6.1 +/- 1.3 nmol of NADPH oxidized/min/mg of protein, respectively. Mean SOD-like activity of spermatozoa separated by centrifugation was 58.6 +/- 22.3 U/mg of protein; SOD-like activity was not detected in Percoll-separated spermatozoa. Among reproductive tissues, the ampulla and prostate had the highest SOD-like activity, although this was not significantly different from activity in other tissues. Testes and spermatozoa from the cauda epididymis contained significantly more GPX activity than other tissues. Results suggest that although equine seminal plasma contains high SOD-like enzyme activity, spermatozoa have limited GPX and SOD-like activity. Enzymatic antioxidant activity in equine spermatozoa appears to be predominantly derived from seminal plasma adsorbed onto the plasma membrane. Removal of seminal plasma during semen processing may increase oxidative stress in equine-spermatozoa.

The effects of propranolol on skeletal muscle contraction, lipid peroxidation products and antioxidant activity in experimental hyperthyroidism

1. The mean levels of lipid peroxidation products, namely conjugated diene and malonaldehyde, were increased in the soleus muscles of hyperthyroid cats, while the mean glutathione peroxidase activity was decreased. No corresponding similar changes were noted in the fast extensor digitorum longus muscles and serum. 2. Propranolol administration prevented the increase in conjugated diene level in the soleus muscles of hyperthyroid cat but not the malonaldehyde level. It also prevented the reduction in glutathione peroxidase activity in the slow oxidative soleus muscles of hyperthyroid cats. 3. Maximal twitch tension, subtetanic tension and maximum tetanic tension of soleus and EDL muscles were reduced in hyperthyroid cats. Propranolol administration for 5 weeks to hyperthyroid cats did not prevent the reduction in tension of contractions of these muscles. 4. It is suggested that lipid peroxidation might not be responsible for the myopathy in hyperthyroidism and propranolol administration does not improve skeletal muscle function in hyperthyroid animals.

Glutathione Peroxidase and Selenium Levels in the Preterm Infant

Glutathione peroxidase (GPX) and selenium are important in the prevention of cellular oxidant damage. Whole-blood GPX and plasma selenium were measured at birth and sequentially afterwards in 75 preterm babies. GPX activity at birth was 2.74 +/- 0.08 (mean +/- SEM) U/ml. Mean GPX activity remained relatively unchanged for up to 70 days postnatal age. Plasma selenium at birth was 0.43 +/- 0.02 (mean +/- SEM) mumol/l), decreasing to low levels by 10 weeks postnatal age. Neither GPX activity nor plasma selenium was related to birth weight, gestational age or infant sex.

Lipid peroxidation and superoxide dismutase-1 and glutathione peroxidase activities in trisomy 16 fetal mice and human trisomy 21 fibroblasts.

An increase in lipid peroxidation has been reported in fetal human trisomy 21 brains. To determine whether this change can be regarded as a consequence of the increase in soluble Cu, Zn-superoxide dismutase (SOD-1) activity caused by the trisomy, we have made use of the trisomy 16 mouse, a model for human trisomy 21. Lipid peroxidation, as malonaldehyde, and the activities of SOD-1 and glutathione peroxidase were studied in diploid and trisomy 16 mouse fetuses and fetal brains and, for comparison, in diploid and trisomy 21 human fibroblasts. SOD-1 activity in diploid mouse brain increased during fetal and postnatal development, but glutathione peroxidase activity was unchanged. Mean SOD-1 activity was almost exactly 50% increased in trisomy 16 fetuses and fetal brains and in human trisomy 21 fibroblasts, confirming the gene dosage effect in both species. The SOD-1 activity in the trisomic fetuses was correlated with that in their matched diploid littermates, suggesting that factors other than the gene dosage also determine activity. Mean glutathione peroxidase activity was not increased in trisomy 16 fetuses or brains and only slightly increased in human trisomy 21 fibroblasts. Mean lipid peroxidation was decreased in fetal trisomy 16 brains but was increased in human trisomy 21 fibroblasts. These results do not lend support to the notion that increased SOD-1 activity is developmentally deleterious and necessarily increases lipid peroxidation and, secondarily, the activity of glutathione peroxidase. The difference between the human and mouse data concerning lipid peroxidation in trisomic brains may be related to structural differences in the lipids which provide the substrate for lipid peroxidation.

Quantitative and qualitative aspects of selenium utilization in pregnant and nonpregnant women: an application of stable isotope methodology

Selenium utilization of women in early and late pregnancy was compared to that of nonpregnant controls. A defined diet providing about 150 micrograms Se/day was fed for 20 days, and selenium balance was measured during the last 12 days. Net selenium retentions of the women in early and late pregnancy were 10 and 23 micrograms/day, respectively, but probably are inflated estimates of the increased selenium requirement during pregnancy. Apparent absorption of selenium was 80% for all three groups. Pregnant women tended to conserve selenium by decreasing urinary selenium excretion. Those observations were corroborated by monitoring the urinary and fecal excretion of 40 micrograms of a stable isotope of selenium (76Se) from intrinsically labeled egg. The isotope data also indicated that recent selenium intake was incorporated into a long-term selenium pool. Mean glutathione peroxidase activity was lower in plasma and higher in platelets in the pregnant women as compared to controls, but the physiological significance of those observations is unknown.

Glutathione peroxidase in human cerebrospinal fluid

Glutathione peroxidase activity was investigated in human cerebrospinal fluid. CSF was obtained from 23 male adult patients with dementia, cerebrovascular disease and multiple sclerosis. The mean glutathione peroxidase activity in the CSF was 6.2 nmol NADPH oxidized min-1 . mg-1 protein +/- 0.6 S.E.M. No differences in the activities were observed in these neurological diseases suggesting that this value may reflect normal glutathione peroxidase activity in human CSF. The age or the protein concentration in CSF did not correlate significantly with glutathione peroxidase activity in CSF.

The selenium state of children. II. Selenium content of serum, whole blood, hair and the activity of erythrocyte glutathione peroxidase in dietetically treated patients with phenylketonuria and maple-syrup-urine disease.

The selenium content of serum, whole blood and hair was measured by neutron activation analysis in dietetically treated patients with phenylketonuria (PKU) and maple-syrup-urine disease (MSUD). Follow-up studies showed a decrease of the serum selenium content and the glutathione peroxidase activity of erythrocytes--a selenoenzyme--from normal values at the beginning of the diet to 20% (selenium) and 50% (gluthione peroxidase) of normal within 10--12 weeks of dietary treatment. In 36 patients the serum selenium content was lower at 6.7--28 X 10(-9) g/ml, independent of the age of the patients (0.5 to 10 years). The selenium content of whole blood was reduced: median = 98 X 10(-9) g/g dry weight; range 75 to 165 X 10(-9) g/g dry weitht (healthy children: median = 381 X 10(-9) g/g dry weight; range 245 to 588 X 10(-9) g/g dry weight). The selenium content of hair was markedly lower in the patients (median = 62 X 10(-9) g/g; range 13--140 X 10(-9) g/g) than in healthy children (median = 429; range 213 to 720 X 10(-9) g/g). The mean glutathione peroxidase activity of erythrocytes was reduced to 4.6 +/- 0.64 U37/g Hb, comparison to normal values (mean = 8.8 +/- 0.88 U37/g Hb).