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Alteration in glutathione metabolism during cataract progression.

Human cataractous lenses obtained from eye relief camp showed decreased levels of sulphydryl and glutathione. Significant depletion in activities of glutathione reductase, glutathione peroxidase and glucose-6-phosphate dehydrogenase was also encountered. These findings indicated an impairment in glutathione metabolism of the mature cataractous lenses as compared to immature lenses, and oxidative stress could be considered as a primary event in this process.

Cataract↗

Proatherogenic and antiatherogenic effects of probucol and phytosterols in apolipoprotein E-deficient mice: possible mechanisms of action.

BACKGROUND: The effects of probucol and a phytosterol mixture (FCP-3PI) on atherosclerotic lesion formation, plasma lipoproteins, hepatic and lipoprotein lipase activities, antioxidant enzyme activities, and plasma fibrinogen were investigated in apolipoprotein E-knockout (apoE-KO) mice. METHODS AND RESULTS: Three groups of 8 mice were fed a diet containing 9% (wt/wt) fat (controls) or the foregoing diet supplemented with either 1% (wt/wt) probucol (the probucol group) or 2% (wt/wt) FCP-3PI (the FCP-3PI group) for 20 weeks. Compared with controls, atherosclerotic lesion size was 3 times greater in the probucol group, whereas it was decreased by half in the FCP-3PI group. Probucol treatment resulted in high plasma probucol concentrations, which correlated (r=0.69) with the lesion area. HDL cholesterol was reduced (>75%) in the probucol group and slightly increased (14%) in the FCP-3PI-treated group. Postheparin lipoprotein lipase (LPL) activity was significantly reduced in both treatment groups, but only FCP-3PI significantly decreased hepatic lipase activity. Plasma fibrinogen was increased 42% by probucol and decreased 19% by FCP-3PI relative to controls. Probucol significantly increased plasma glutathione reductase, glutathione peroxidase, and superoxide dismutase activities (P<0.05). In contrast to findings in apoE-KO mice, there was no probucol-induced atherosclerosis in their wild-type counterparts fed the same dose for the same period of time. CONCLUSIONS: Antiatherogenic activity of FCP-3PI in apoE-KO mice is associated with an increase in HDL cholesterol concentration along with decreases in hepatic lipase activity and plasma fibrinogen concentrations. Proatherogenic effects of probucol may be related to increased plasma fibrinogen, decreased HDL cholesterol concentrations along with decreased LPL activity, or its direct "toxicity" due to very high plasma concentration. Our studies demonstrate that the antioxidant and cholesterol-lowering properties of probucol do not prevent atherogenesis in this particular animal model.

Animals↗

Deprenyl effects on levodopa pharmacodynamics, mood, and free radical scavenging.

Clinical evidence suggests that deprenyl may slow progression of Parkinson's disease, although mechanisms underlying this putative neuroprotective action remain poorly understood. To address this issue, we studied deprenyl in 12 parkinsonian patients using a single-blind, placebo-controlled, crossover design. After 1 month, deprenyl (10 mg/d) decreased the optimal levodopa requirement by 24% (oral) and 16% (intravenous). Levodopa-induced dyskinesias were prolonged by 430%, and antiparkinsonian action by 44%. Mood improved by 47%. One month after withdrawing deprenyl, effects on dyskinesias and mood had yet to return to baseline. There was no change in activities of circulating glutathione peroxidase, glutathione reductase, glutathione transferase, superoxide dismutase, and catalase, nor in levels of lipid peroxide and vitamin E. Deprenyl also failed to modify CSF levels of total glutathione and activities of glutathione peroxidase or superoxide dismutase. These effects on levodopa pharmacodynamics and mood complicate the interpretation of available investigations of deprenyl's neuroprotective action and increase the risk of adverse effects of levodopa.

Affect↗

Protective effect of diethyldithiocarbamate pretreatment on chromium (VI)-induced cytotoxicity and lipid peroxidation in primary cultures of rat hepatocytes.

Pretreatment of primary cultures of rat hepatocytes with sodium diethyldithiocarbamate (DDTC) for 15 min prior to exposure to K2Cr2O7 resulted in a marked decrease in dichromate-induced cytotoxicity, as evaluated by the leakage of lactate dehydrogenase, and in lipid peroxidation, as monitored by malondialdehyde formation. In addition, pretreatment with DDTC attenuated the suppression of the level of vitamin E attributed to K2Cr2O7. However, DDTC pretreatment had no effect on the cellular levels of glutathione or vitamin C or on the activity of the glutathione reductase, glutathione peroxidase, superoxide dismutase or alkaline phosphatase suppressed by dichromate. Under the same experimental conditions, cellular uptake or distribution of chromium was not affected by DDTC. These results indicate that the protective effect of DDTC on chromium (VI)-induced cytotoxicity as well as lipid peroxidation may be associated with the level of nonenzymatic antioxidants such as vitamin E.

Alkaline Phosphatase↗

Selenium status in an iodine deficient population of the West Ivory Coast.

Selenium is an essential trace element which is part of the active site of seleno-dependent glutathione peroxidase and type 1 deiodinase. Therefore, it plays a key role in thyroid hormone metabolism. The present work was undertaken in order to evaluate selenium status in two Ivory Coast populations: the first with high (Glanlé) and the second with low (Abidjan) prevalence of iodine deficiency. Selenium, glutathione peroxidase, glutathione reductase, glutathione and diglutathione were determined in blood and/or urine. In plasma and erythrocytes, selenium and glutathione peroxidase were dramatically low in Glanlé. Compared to Abidjan, selenium, glutathione peroxidase, vitamin E and riboflavin status were decreased whereas diglutathione was increased in Glanlé. The results clearly demonstrate a selenium deficiency and suggest an oxidant stress in Glanlé. Causes and consequences of this selenium deficiency and oxidant stress remain to be determined.

Anthropology, Cultural↗

Protection by pantothenol and beta-carotene against liver damage produced by low-dose gamma radiation.

Rats were exposed to a total dose of 0.75 Gy of gamma radiation from a 60Co source, receiving three doses of 0.25 Gy at weekly intervals. During two days before each irradiation, the animals received daily intragastric doses of 26 mg pantothenol or 15 mg beta-carotene per kg body mass. The animals were killed after the third irradiation session, and their blood and livers were analyzed. As found previously (Slyshenkov, V.S., Omelyanchik, S.N., Moiseenok, A.G., Trebukhina, R.V. & Wojtczak, L. (1998) Free Radical Biol. Med. 24, 894-899), in livers of animals not supplied with either pantothenol or beta-carotene and killed one hour after the irradiation, a large accumulation of lipid peroxidation products, as conjugated dienes, ketotrienes and thiobarbituric acid-reactive substances, could be observed. The contents of CoA, pantothenic acid, total phospholipids, total glutathione and GSH/GSSG ratio were considerably decreased, whereas the NAD/NADH ratio was increased. All these effects were alleviated in animals supplied with beta-carotene and were completely abolished in animals supplied with pantothenol. In the present paper, we extended our observations of irradiation effects over a period of up to 7 days after the last irradiation session. We found that most of these changes, with the exception of GSH/GSSG ratio, disappeared spontaneously, whereas supplementation with beta-carotene shortened the time required for the normalization of biochemical parameters. In addition, we found that the activities of glutathione reductase, glutathione peroxidase, catalase and NADP-dependent malate (decarboxylating) dehydrogenase ('malic enzyme') in liver were also significantly decreased one hour after irradiation but returned to the normal level within 7 days. Little or no decrease in these activities, already 1 h after the irradiation, could be seen in animals supplemented with either beta-carotene or pantothenol. It is concluded that pantothenol is an excellent radioprotective agent against low-dose gamma radiation.

Animals↗

Abnormal erythrocyte metabolism in hepatic disease.

Erythrocyte (RBC) metabolic studies were done on 114 patients with severe hepatic disease. Heinz body formation after incubation of RBCs with acetyl phenylhydrazine was found to be significantly higher in patients than in controls. RBC-reduced glutathione levels were lower than those of controls both before and after incubation with acetyl phenylhydrazine, and patients with the highest Heinz body counts had the lowest reduced glutathione levels. RBC methylene blue-stimulated hexose monophosphate (HMP) shunt metabolism and glucose recycling through the shunt were significantly lower in patients with active hepatic disease than in controls. There was no difference in resting HMP shunt activity or in resting recycling of glucose. Despite impairment of shunt metabolism, total glucose consumption was greater in patients than in controls. The patients with the lowest stimulated HMP shunt metabolism and glucose recycling had the highest Heinz body counts, lowest reduced glutathione, and highest total glucose consumption. A continuum of abnormal shunt metabolism was seen, from a mild reduction of stimulated HMP shunt activity to a severe combined decrease in both the HMP shunt and glucose recycling. When measured, glutathione reductase, glutathione peroxidase, glucose-6-phosphate dehydrogenase, and transketolase were normal or increased. Sequential studies were done on 11 patients who had abnormal metabolic studies. Coincident with improvement of HMP shunt metabolism, the Heinz body counts became lower, reduced glutathione higher, hematocrit higher, and liver function improved. Impaired HMP shunt metabolism appears to be a common, acquired RBC abnormality in patients with severe, active liver disease.

Erythrocytes↗

Red cell enzyme deficiencies as non-disease.

Many red cell enzyme defects have been discovered, many of them in patients with hemolytic anemia. In some cases a cause-and-effect relationship between the enzyme deficiency and shortening of red cell life span has been clearly documented. However, some enzyme deficiencies are well tolerated by the erythrocyte, appearing to produce no impairment in function. These include deficiencies in catalase, galactokinase, UDPGlu-4-epimerase, NADPH diaphorase, phosphoglucomutase, acetylcholinesterase, glutathione reductase, glutathione peroxidase, and adenylate kinase. The capacity of the erythrocyte to tolerate deficiencies in these enzymes indicates either that the metabolic pathways which the enzyme serves are not required by the red cell or that redundancies in metabolism exist which allow the erythrocyte to compensate for the enzyme deficiency.

Acatalasia↗

Heterologous expression of selenium-dependent glutathione peroxidase affords cellular resistance to paraquat.

Transfection of murine NIH3T3 fibroblasts and human MCF7 breast carcinoma cells with a pSV2-derived eukaryotic expression vector for human cytosolic glutathione peroxidase resulted in clones with increased glutathione peroxidase activity. This heterologous expression indicates that murine cells recognize the human "selenocysteine insertion sequence" in the 3' untranslated region of the mRNA which facilitates insertion of selenocysteine directed by the opal codon. Though most clones from both cell lines eventually lost their enhanced glutathione peroxidase activity despite continuous selection on G418, some NIH3T3 clones retained enhanced enzyme activity without continuous G418 exposure. Transfection of MCF7 cells with an Epstein-Barr virus (EBV)-derived episomally replicating expression vector carrying the glutathione peroxidase gene also revealed increased glutathione peroxidase activity. These MCF7 cells, however, all required exposure to G418 to maintain enhanced glutathione peroxidase activity. Detailed biochemical analysis of a stably expressing NIH3T3 clone and MCF7 expressing cells revealed no alterations in activities of copper-zinc superoxide dismutase, manganese superoxide dismutase, catalase, phospholipid-glutathione peroxidase, glutathione reductase, glutathione transferase, or NADPH-P450 reductase. Both pSV2- and EBV-derived glutathione peroxidase-expressing clones exhibited enhanced resistance to paraquat as well as to peroxides.

3T3 Cells↗

Responses of glutathione-related enzymes in isolated rat small intestine to Fe(2+)-EDTA-mediated oxidative stress.

The activities of glutathione-related enzymes in isolated rat small intestine were investigated under oxidative stress mediated by Fe(2+)-EDTA. The isoelectric points and approximate molecular weights of the enzymes investigated were first determined. The reduced and oxidized glutathione contents, and low molecular weight thiols in isolated rat small intestine were also studied under oxidative stress. Significant reducing activities of glutathione S-transferase and lactate dehydrogenase were observed accompanied by increases in oxidized glutathione content, whereas thioltransferase, glutathione reductase, glutathione peroxidase and thioredoxin reductase retained the same levels of activity as controls. First-order inactivation of purified rat small intestine glutathione S-transferase including class-alpha, mu and pi was observed and the isozyme class-pi was inactivated at several pH's under Fe(2+)-EDTA-mediated oxidative stress. Leakage of protein and both reduced and oxidized forms of glutathione was significantly increased during incubation with Fe(2+)-EDTA. In conclusion, enzymes which were not inactivated under Fe(2+)-EDTA-mediated oxidative stress may play an important role in cellular antioxidant defenses in the small intestine. Furthermore, enzymes such as glutathione S-transferase, mainly a class-pi isozyme, and lactate dehydrogenase which were inactivated may form part of the barrier against oxidative stress similar to reduced glutathione.

Animals↗

A comparative study on effect of dietary selenium and vitamin E on some antioxidant enzyme activities of liver and brain tissues.

Since selenium and vitamin E have been increasingly recognized as an essential element in biology and medicine, current research activities in the field of human medicine and nutrition are devoted to the possibilities of using these antioxidants for the prevention or treatment of many diseases. The present study was aimed at investigating and comparing the effects of dietary antioxidants on glutathione reductase and glutathione peroxidase activities as well as free and protein-bound sulfhydryl contents of rat liver and brain tissues. For 12-14 wk, both sex of weanling rats were fed a standardized selenium-deficient and vitamin E-deficient diet, a selenium-excess diet, or a control diet. It is observed that glutathione reductase and glutathione peroxidase activities of both tissues of the rats fed with a selenium-deficient or excess diet were significantly lower than the values of the control group. It is also shown that free and bound sulfhydryl concentrations of these tissues of both experimental groups were significantly lower than the control group. The percentage of glutathione reductase and glutathione peroxidase activities of the deficient group with respect to the control were 50% and 47% in liver and 66% and 61% in the brain, respectively; while these values in excess group were 51% and 69% in liver and 55% and 80% in brain, respectively. Free sulfhydryl contents of the tissues in both experimental groups showed a parallel decrease. Furthermore, the decrease in protein-bound sulfhydryl values of brain tissues were more pronounced than the values found for liver. It seems that not only liver but also the brain is an important target organ to the alteration in antioxidant system through either a deficiency of both selenium and vitamin E or an excess of selenium alone in the diet.

Animal Nutritional Physiological Phenomena↗

Salix caprea inhibits skin carcinogenesis in murine skin: inhibition of oxidative stress, ornithine decarboxylase activity and DNA synthesis.

Chemoprevention of free radical-mediated diseases including cancer by natural products is an emerging discipline due to its wider applicability and acceptance. The present study deals with the chemopreventive effect of Salix caprea against phorbol ester-induced oxidative stress and tumor promotion in murine skin. In the present investigation, it was observed that a single application of 12-O-tetradecanoyl-13-phorbol acetate (TPA) (20 nmol/0.2 ml acetone/animal) caused a significant (P < 0.05) depletion of cutaneous antioxidants viz., glutathione, glutathione reductase, glutathione peroxidase, catalase and phase II drug metabolizing enzymes viz., glutathione-S-transferase, quinone reductase. An increase in the hydrogen peroxide generation and protein oxidation (measured in terms of protein carbonyl content) was also observed with a single application of TPA. However, the pretreatment of animals with different doses of Salix caprea (0.5, 1.0 and 1.5 mg/kg/0.2 ml acetone) caused a significant recovery in the TPA-mediated depletion in antioxidant levels. The pretreatment of animals with Salix caprea was observed to inhibit the TPA-mediated depletion in phase II enzymes. It was also observed that Salix caprea reversed the TPA-mediated depletion in the activity of phase II enzymes that is an important characteristic of cancer chemopreventive agents. Phorbol esters are known to induce the tumor promotion by increasing rate of DNA synthesis, ornithine decarboxylase activity (ODC), and xanthine oxidase activity. In the present investigation, it was observed that the pretreatment of animals with Salix caprea caused a significant (P < 0.05) depletion in the TPA-induced DNA synthesis, ODC and xanthine oxidase activity in mice skin. Salix caprea significantly reduced the tumor promotion in mice skin when tested in two-stage chemical carcinogenesis model. It was observed to inhibit significantly P < 0.05) the 7,12-dimethyl benz[a] anthracene (DMBA)-initiated phorbol ester promoted skin carcinogenesis. It was concluded from the results that Salix caprea is an effective antioxidant and chemopreventive agent against phorbol ester-induced tumor promotion.

Administration, Cutaneous↗

Alterations in Cd-induced gene expression under nitrogen deficiency in Hordeum vulgare.

The inter-relation between nitrogen availability and cadmium toxicity was studied in roots of barley seedlings with emphasis on the analysis of expression of 10 selected genes relevant for growth in the presence of toxic Cd concentrations. The response to Cd exposure differed quantitatively or qualitatively for the 10 genes in dependence of the N supply. Transcripts of glutathione synthase, glutathione reductase, glutathione peroxidase and dehydroascorbate reductase were measured as parameters involved in antioxidant defence, metallothionein, phosphoenolpyruvate carboxylase and phytochelatin synthase (PCS) were analysed as genes related to heavy metal binding, and vacuolar ATPase subunits VHA-E and VHA-c and a NRAMP-transporter as genes being implicated in Cd transport. Reprogramming of the Cd response was most obvious for PCS and NRAMP whose transcript levels were unaltered and down-regulated, respectively, in the presence of Cd at adequate N, but strongly up-regulated upon Cd exposure under conditions of nitrogen deficiency. Different responses to Cd at varying N supply were also seen for the antioxidant genes. The results on gene expression are discussed in context with the changes in biochemical parameters, and underline the importance of evaluating the general growth conditions of a plant when discussing its specific response to a stressor such as Cd. The sequence of the nramp cDNA was filed at the EMBL/GenBank/DDBJ Databases under the accession number AJ514946.

Journal Article↗

[Regulation by catecholamines and cAMP of enzymes of thiol and disulfide metabolism].

In vivo exo- and endogenous catecholamines have no influence on the activities of thioredoxin reductase, glutathione reductase, thiol transferase and nonselenium-dependent glutathione peroxidase. At the same time catecholamines activate via beta-adrenoceptors glutathione S-transferase and selenium-dependent glutathione peroxidase from many tissues and inhibit gamma-glutamyl transferase from kidney. In vitro cAMP has identical effects on the activities of the above enzymes. The possible significance of regulation of glutathione metabolism enzymes is discussed.

Adrenergic alpha-Agonists↗

Toxicity of an anthraquinone violet dye mixture following inhalation exposure, intratracheal instillation, or gavage.

Anthraquinone dyes are utilized by the military in colored-smoke grenades. During production, workers in munitions plants may be exposed to fugitive emissions of these dyes or mixtures thereof. The effects of a prototype violet dye mixture (VDM) consisting of Disperse Red 11 (DR11), [1,4-diamino-2-methoxy-anthraquinone] and Disperse Blue 3 (DB3) [1-methylamino-4-hydroxyethylamino-anthraquinone] on F344 male and female rats have been investigated. Acute 1-day inhalation exposures (6 hr) to VDM were conducted at 1000, 300, 100, 70, 40, and 10 mg/m3, with an additional exposure to 40 mg/m3 6 hr/day for 5 days; 4.22 +/- 2.1 microns (MMAD +/- delta g). Lung burdens of dye, general histopathology, and/or liver function were evaluated at 0, 3, and 7 days postexposure. Unexpected lethality due to severe liver damage was observed with acute exposures of > or = 300 mg/m3 and in the 5-day 40 mg/m3 exposures. Centrilobular degeneration and necrosis of liver cells was concentration-dependent with inhalation of VDM > or = 40 mg/m3. In addition, nasal olfactory epithelium exhibited degeneration and necrosis with acute exposures > or = 10 mg/m3. Lung instillations at 250, 500, and 1000 micrograms of the VDM revealed no lung or liver toxicity. Because per os exposure due to preening was suspected as a major exposure route, a gavage study with the VDM and its two component dyes DR11 and DB3 (800 mg/kg) was undertaken. One day following gavage with DR11 or DB3, serum enzymes indicative of liver toxicity (LDH, SGPT, SDH, and ICDH) were slightly elevated (1-6x control). However, rats gavaged with VDM had serum enzyme levels 10-100x control by Day 1 after gavage, indicating acute liver toxicity. Activities of liver enzymes involved in xenobiotic and glutathione metabolism were also acutely affected. All of the dyes caused various degrees of induction of glucose-6-phosphate dehydrogenase, glutathione reductase, glutathione peroxidase, and nonprotein sulfhydryls. The enzymes involved in xenobiotic metabolism (glutathione S-transferase, NADPH cytochrome-c reductase, and P450) were also elevated by the two component dyes, in contrast to their significant depression with VDM treatment. The similarity between the liver and olfactory epithelium effects of these compounds and the lack of pulmonary tissue effects is not fully understood, but the interaction of the individual dyes as VDM emphasizes the need to assess chemicals such as the anthraquinones as their likely-to-be-encountered mixtures.

Administration, Inhalation↗

Energy dissipation and radical scavenging by the plant phenylpropanoid pathway.

Environmental stresses such as high light, low temperatures, pathogen infection and nutrient deficiency can lead to increased production of free radicals and other oxidative species in plants. A growing body of evidence suggests that plants respond to these biotic and abiotic stress factors by increasing their capacity to scavenge reactive oxygen species. Efforts to understand this acclimatory process have focused on the components of the 'classical' antioxidant system, i.e. superoxide dismutase, ascorbate peroxidase, catalase, monodehydroascorbate reductase, glutathione reductase and the low molecular weight antioxidants ascorbate and glutathione. However, relatively few studies have explored the role of secondary metabolic pathways in plant response to oxidative stress. A case in point is the phenylpropanoid pathway which is responsible for the synthesis of a diverse array of phenolic metabolites such as flavonoids, tannins, hydroxycinnamate esters and the structural polymer lignin. These compounds are often induced by stress and serve specific roles in plant protection, i.e. pathogen defence, ultraviolet screening, antiherbivory, or structural components of the cell wall. This review will highlight a novel antioxidant function for the taxonomically widespread phenylpropanoid metabolite chlorogenic acid (CGA; 5-O-caffeoylquinic acid) and assess its possible role in abiotic stress tolerance. The relationship between CGA biosynthesis and photosynthetic carbon metabolism will also be discussed. Based on the properties of this model phenolic metabolite, we propose that under stress conditions phenylpropanoid biosynthesis may represent an alternative pathway for photochemical energy dissipation that has the added benefit of enhancing the antioxidant capacity of the cell.

Antioxidants↗

Alteration of antioxidant status following sympathectomy: differential effects of modified plasma levels of adrenaline and noradrenaline.

The influence of altered levels of endogenous catecholamines following adrenalectomy or 6-hydroxydopamine (6-OH) treatment (alone or in combination) on enzymatic (glutathione reductase, catalase, glutathione peroxidase and Cu, Zn superoxide dismutase) and non-enzymatic (glutathione) antioxidant components of heart, liver, kidney, lung and erythrocytes in male Wistar rats was investigated. Functional antioxidant status was assessed in terms of susceptibility to t-butylhydroperoxide-induced sulfhydryl group oxidation (an indirect measure of glutathione depletion) and lipid peroxidation, as measured by thiobarbituric acid-reactive substance (TBARS) formation. Reduced levels of adrenaline and noradrenaline resulted from adrenalectomy and 6-OH treatment, respectively, while a combination of these treatments led to a reduction in the levels of both catecholamines. Adrenalectomy was associated with alterations in glutathione reductase activity in the heart and liver (increased). 6-OH treatment alone produced an elevation in glutathione reductase activity only in the heart. In adrenalectomized animals, 6-OH treatment produced no further increases in glutathione reductase activities of heart or liver. In lung, however, the combination of adrenalectomy and 6-OH treatment caused an elevation in both glutathione peroxidase and glutathione reductase activities. Glutathione levels of liver alone were elevated following adrenalectomy, while those of erythrocytes and liver (but not other tissues investigated) were increased by the combination of adrenalectomy and 6-OH treatment. The kidney was relatively resistant to the effects of sympathectomy and showed no changes in any of the antioxidant components measured. Adrenalectomy alone or in combination with 6-OH produced an increased in susceptibility to peroxide-induced sulfhydryl group oxidation only in the heart. 6-OH treatment caused a reduction in peroxide-induced TBARS formation only in the kidney. Both adrenalectomy and the combination of adrenalectomy and 6-OH treatment were associated with reduced TBARS formation in the liver, lung and kidney, but not heart. Results from this study demonstrate that the effects of sympathectomy on antioxidant status vary among tissues. Differences between adrenalectomy and 6-OH treatment on antioxidant components are suggestive of differential actions of adrenaline and noradrenaline on tissue antioxidant status which may have important implications under conditions associated with elevations in levels of these catecholamines including chronic stress and myocardial infarction.

Adrenalectomy↗

Relationship among standard semen parameters, glutathione peroxidase/glutathione reductase activity, and mRNA expression and reduced glutathione content in ejaculated spermatozoa from fertile and infertile men.

OBJECTIVE: To determine the expression and enzymatic activity of glutathione peroxidase (GPX)-1, GPX-4, and glutathione reductase together with glutathione (GSH) concentrations in spermatozoa from fertile and infertile men. DESIGN: Prospective study. SETTING: University-affiliated private center. PATIENT(S): Fifty-four infertile men undergoing assisted reproduction techniques and 55 fertile sperm donors with pregnancies and newborns by artificial insemination. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Analysis of gene expression by fluorescent quantitative polymerase chain reaction and an analysis of enzymatic activity and GSH concentration by controlled biochemical reactions and spectrophotometry. RESULT(S): GPX-4 activity but not mRNA expression is directly related to sperm morphology (strict criteria) and is more compromised with a low percentage of normal sperm. These differences are also demonstrated when fertile and infertile men were compared. In addition, intracellular GSH concentrations are lower when sperm morphology is severely impaired, but no differences were found between fertile and infertile men. CONCLUSION(S): Intracellular sperm GSH system components GPX-4 and GSH are altered in infertile men, and these alterations seem to be linked to sperm morphology.

Case-Control Studies↗