Glutathione metabolism and antioxidant enzymes in patients affected by nonalcoholic steatohepatitis

BACKGROUND: Oxidative stress and accumulation of excessive fat in the liver may underlie the pathophysiology of nonalcoholic steatohepatitis (NASH). Given that glutathione blood metabolism may represent an indicator of tissue oxidative status, we analysed the blood profile of various forms of glutathione in children with NASH, and we evaluated the presence of systemic oxidative stress by calculating the oxidised/reduced glutathione ratio (GSSG/GSH). Furthermore, we analysed the catalytic activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione transferase (GST), and glutathione reductase (GR) in blood of patients. METHODS: Blood samples were obtained from 21 children with NASH and 28 controls. Total, reduced, oxidised, and protein-bound glutathione concentrations were determined by reversed-phase liquid chromatography with fluorescence detection. Antioxidant enzymes were spectrophotometrically assayed by using specific substrates. RESULTS: Our findings showed a 1.5-fold increase of GSSG in patients, resulting in a significant rise of the GSSG/GSH ratio. SOD, GPx, and GR activities were not significantly different in NASH respect to controls, whereas GST, which provides the second defence line against oxidative stress, was 17.8% increased. CONCLUSIONS: Our data demonstrate an impairment of glutathione metabolism and antioxidant enzyme activities in blood of patients with NASH, supporting a consistent role of free radical cytotoxicity in the pathophysiology of the disease.     

Peripheral oxidative stress in relapsing-remitting multiple sclerosis

ObjectivesTo evaluate levels of oxidative stress in blood samples in patients with relapsing–remitting MS (RR-MS).Design and methodsPeripheral blood samples were collected from 24 RR-MS patients and 15 healthy controls. Levels of the following were measured: carbonylated proteins, 8-hydroxy-2′deoxyguanosine (8OHdG), total glutathione, reduced glutathione (GSH), oxidized glutathione (GSSG), GSH/GSSG ratio, superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GRd), glutathione-S-transferase (GST), myeloperoxidase (MPO), antioxidant gap, total antioxidant capacity (PAO), global oxidative stress (GOS), serum vascular cell adhesion molecule-1 (sVCAM-1) and serum inter-cellular adhesion molecule 1 (sICAM-1).ResultsValues for carbonylated proteins, 8OHdG, total glutathione, GSH, GSH/GSSG ratio, SOD, GRd and GOS were significantly higher in RR-MS patients than in healthy controls. By contrast, PAO, GSSG, GPx and GST were lower in RR-MS patients.ConclusionOxidative stress plays a major role in MS, and is observed prior to relapse.     

Laryngeal cancer: in relation to oxidative stress

This study was designed to investigate the oxidative stress parameters in laryngeal cancer and cancer-free adjacent tissues. Lipid peroxidation end product and the endogenous antioxidant components-CuZn superoxide dismutase (CuZn SOD) glutathione peroxidase (GSH Px), glutathione reductase (GSSG Rd) and glutathione (GSH)-were analysed by spectrophotometric and kinetic methods. Laryngeal cancer tissue exhibited higher lipid peroxidation than cancer free adjacent tissue. CuZn SOD and GSH Px activities and GSH level were significantly higher and GSSG Rd activity significantly lower in the cancer tissue. Detection of the antioxidant status may be useful to determine the tumour resistance to therapy, to choose the correct radiotherapy/chemotherapy and to monitor the effectiveness of the therapetic strategy.     

Glutathione status in the blood and tissues of patients with virus-originated hepatocellular carcinoma

OBJECTIVES: Glutathione status can be regarded as the redox status for many diseases. This study was performed to investigate the glutathione status in virus-originated hepatocellular carcinoma (HCC). DESIGN AND METHODS: The blood and tissue samples were obtained from 24 patients. Blood samples were also obtained from 137 controls for comparison. RESULTS: The GSH level and the ratios of GSH/GSSG and GSH/total glutathione of the blood samples from the patients were significantly lower than those of the controls, while the GSSG values were significantly higher. Meanwhile, levels of GSH and total glutathione, as well as the ratios of GSH/GSSH and GSH/total glutathione, were significantly decreased, whereas GSSG levels were significantly higher, in the HCC tissues than those of the adjacent cancer-free tissues. CONCLUSIONS: Glutathione status in the HCC suggested that the antioxidant system is severely impaired, supporting a consistent role of the free radical cytotoxicity in the pathophysiology of the disease.     

Oxidant-antioxidant status in patients with oral squamous cell carcinomas at different intraoral sites

OBJECTIVES: To compare the extent of lipid peroxidation and the status of antioxidants in tumor and venous blood of patients with oral squamous cell carcinoma (OSCC) at different intraoral sites. DESIGN AND METHODS: Twenty four patients with OSCC at different intraoral sites and an equal number of age- and sex-matched reference subjects were chosen for the study. The concentrations of lipid peroxides and reduced glutathione (GSH) and the activities of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione-S-transferase (GST) were estimated in tissues and blood. RESULTS: Diminished lipid peroxidation in tumor tissue was accompanied by decreased activities of SOD and CAT with increase in GSH and GSH-dependent enzymes. In contrast, enhanced lipid peroxidation with decrease in antioxidants was observed in the venous blood of OSCC patients. CONCLUSION: No significant differences in lipid peroxidation and antioxidant levels were observed between patients with OSCC at different intraoral sites. However, our results revealed differences between the tumor and blood with respect to their susceptibility to lipid peroxidation and antioxidant status.     

Coenzyme Q10 concentrations and antioxidant status in tissues of breast cancer patients

OBJECTIVES: An increasing amount of experimental and epidemiological evidence implicates the involvement of oxygen derived radicals in the pathogenesis of cancer development. Oxygen derived radicals are able to cause damage to membranes, mitochondria, and macromolecules including proteins, lipids and DNA. Accumulation of DNA damages has been suggested to contribute to carcinogenesis. It would, therefore, be advantageous to pinpoint the effects of oxygen derived radicals in cancer development. DESIGN AND METHODS: In the present study, we investigated the relationship between oxidative stress and breast cancer development in tissue level. Breast cancer is the most common malignant disease in Western women. Twenty-one breast cancer patients, who underwent radical mastectomy and diagnosed with infiltrative ductal carcinoma, were used in the study. We determined coenzyme Q10 (Q) concentrations, antioxidant enzyme activities (mitochondrial and total superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase), and malondialdehyde (MDA) levels in tumor and surrounding tumor-free tissues. RESULTS: Q concentrations in tumor tissues significantly decreased as compared to the surrounding normal tissues (p < 0.001). Higher MDA levels were observed in tumor tissues than noncancerous tissues (p < 0.001). The activities of MnSOD, total SOD, GSH-Px and catalase in tumor tissues significantly increased (p < 0.001) compared to the controls. CONCLUSIONS: These findings may support that reactive oxygen species increased in malignant cells, and may cause overexpression of antioxidant enzymes and the consumption of coenzyme Q10. Increased antioxidant enzyme activities may be related with the susceptibility of cells to carcinogenic agents and the response of tumor cells to the chemotherapeutic agents. Administration of coenzyme Q10 by nutrition may induce the protective effect of coenzyme Q10 on breast tissue.     

Protective role of caffeic acid phenethyl ester in the liver of rats exposed to cold stress

Cold exposure can induce a form of environmental stress. Cold stress (CS) alters homeostasis, results in the creation of reactive oxygen species and leads to alterations in the antioxidant defense system. The caffeic acid phenethyl ester (CAPE), an active component of propolis, has an antioxidant capacity. We investigated the effect of CS on oxidative stress and antioxidant defense system and the possible protective effect of CAPE in rat liver tissue. Twenty-four female Wistar Albino rats were divided into four groups: Control, CAPE-treated, CS, and CAPE-treated CS (CS + CAPE) group. Catalase (CAT), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) activities and total glutathione (GSH) and malondialdehyde (MDA) levels were measured. In addition, histological changes in liver tissue were examined by light microscopy. SOD, CAT and GSH-Px activities and total GSH level were significantly declined in the CS group. In the CS + CAPE group, the activities of these three enzymes and GSH level significantly raised with regard to the CS group. MDA levels increased in the CS group and decreased in the CS + CAPE group. The tissues of the CS group showed some histopathological changes such as necrosis, hepatocyte degeneration, sinusoidal dilatation, hemorrhage and vascular congestion and dilatation. In the CS + CAPE group, the histopathological evidence of hepatic damage was markedly reduced. Histological parameters were consistent with biochemical parameters. In this study, CS increased oxidative stress in liver tissue. CAPE regulated antioxidant enzymes, inhibited lipid peroxidation and reduced hepatic damage.     

Evidence of oxidative and nitrosative stress in patients with cervical squamous cell carcinoma

BACKGROUND: We conducted a study to evaluate reactive oxygen species (ROS) and reactive nitrogen species (RNS) simultaneously together with the antioxidant status in patients with cervical carcinoma. METHODS: We measured lipid peroxidation product, including malondialdehye (MDA), nitric oxide (NO) products, including nitrite (NO(2)(-)), nitrate (NO(3)(-)) and total nitrite (TNO(2)(-)) and antioxidant enzymes in 45 patients with cervical cancer and compared them against 30 healthy controls. RESULTS: Plasma as well as erythrocyte MDA and plasma NO levels was higher (p<0.001) in cervical cancer as compared to healthy controls. Antioxidant enzymes, Superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities, were decreased (p<0.001) whereas glutathione S-transferase (GST) activity was increased (p<0.001) in cervical cancer patients. Lipid peroxidation and NO products accumulation correlated significantly with a deranged antioxidant system. CONCLUSIONS: We demonstrated a possible involvement of both oxidative and nitrosative stress, as evidenced by increased lipid peroxidation and NO levels with altered antioxidant defense system in the pathogenesis of cervical cancer.     

Free radical toxicity and antioxidants in Guillain-Barre syndrome, a preliminary study

BACKGROUND: The generation of reactive oxygen species (ROS) has been implicated in the pathogenesis of a vast array of disease processes including some neurological disorders. METHOD: Ten patients with Guillain-Barre syndrome (GBS) and 10 age and sex-matched controls were included in this study. The erythrocyte glutathione (GSH), superoxide dismutase (SOD) and malondialdehyde (MDA) levels, as well as plasma antioxidant vitamins C and E and serum glutathione-S-transferase (GST) levels were estimated spectrophotometrically. RESULTS: The plasma vitamin E and the serum total glutathione-S-transferase levels were markedly increased in both pre- and post-treated cases of GBS when compared to controls. The erythrocyte glutathione and malondialdehyde levels were significantly reduced in GBS cases when compared to normals. However, plasma vitamin C and erythrocyte superoxide dismutase were not altered when compared to controls. CONCLUSION: Free radical toxicity may have an influence in patients suffering from GBS.     

Oxidative stress in chronic lymphoedema

BACKGROUND: Chronic lymphoedema is one of the most frequent and debilitating complications after surgical and radiological tumour treatment. Prevention and therapy of lymphoedema is therefore an important problem of the rehabilitation of those patients. Aim: To investigate whether chronic lymphoedema results in increased oxidative stress. DESIGN: Prospective case-control study. METHODS: We obtained venous blood samples from patients (n=38) with chronic lymphoedema and determined biomarkers of prooxidative reactions and of antioxidative defense system in the erythrocytes or blood plasma: reduced and oxidized glutathione (GSH and GSSG), and lipid peroxidation products such as malondialdehyde (MDA) and 4-hydroxynonenal (HNE). Healthy volunteers (n=90) and patients who had undergone surgical and/or radiotherapeutic treatment of tumours without consequent lymphoedema (n=20) acted as controls. RESULTS: The blood of patients with chronic lymphoedema contained lower concentrations of GSH and higher levels of GSSG and of MDA and HNE, compared with the control group. MDA was increased by about three-fold in the serum of the lymphoedema patients. Accelerated free radical formation and lipid peroxidation processes were further demonstrated by the liberation of MDA and HNE into the blood serum after manual lymph drainage. DISCUSSION: Our data demonstrate enhanced formation of reactive oxygen species (ROS) and accelerated lipid peroxidation processes in chronic lymphoedematous tissue. The strengthening of antioxidative defense mechanisms could be useful in the therapy of chronic lymphoedema.     

Activity of selected enzymes in erythrocytes and level of plasma antioxidants in response to single whole‐body cryostimulation in humans

The influence of extremely low temperatures on the human body and physiological reactions is not fully understood. The aim of this research was to estimate the influence of a single exposure to cryogenic temperature (?130°C), without subsequent kinesiotherapy, on the activity of the most crucial antioxidant enzymes in erythrocytes: superoxide dismutase (SOD), catalase (CAT), glutathione reductase (R‐GSSG), glutathione peroxidase (GPx) and glutathione transferase (T‐GSH). In the plasma, the concentrations of glutathione, uric acid, albumins and extra‐erythrocyte haemoglobin as components of the non‐enzymatic antioxidant system were evaluated. The subjects were 10 healthy young men. Blood was sampled in the morning on the day of cryostimulation, 30?min after cryostimulation and the next morning. The enzymatic response of the antioxidant defence to the influence of the extremely low temperature resulted in an immediate, significant, increase in GPx and R‐GSSG activities, but a decrease in CAT and T‐GSH activities. We observed an increase in the concentrations of all the examined non‐enzymatic antioxidants, especially extra‐erythrocyte haemoglobin and uric acid, which had both increased further the day after cryostimulation. The results indicate that a single stimulation with cryogenic temperatures results in oxidative stress in a healthy body, but that the level of stress is not very high. It seems that in this case the most significant role in the antioxidant mechanisms is played by peroxidase.     

Biochemical studies on the cardioprotective effect of glutamine on tissue antioxidant defense system in isoprenaline-induced myocardial infarction in rats

Oxidative stress is one of the mechanisms with a central role involved in the pathogenesis of myocardial infarction. The protective effect of glutamine on myocardial antioxidant defense system was investigated during isoprenaline-induced myocardial infarction, an animal model of myocardial infarction of human beings. Levels of diagnostic marker enzymes in plasma, reduced glutathione (GSH) and lipid peroxides and the activities of glutathione peroxidase, glutathione-S-transferase, catalase and superoxide dismutase in heart tissue were determined. Injection of isoprenaline caused significant increases in the levels of diagnostic marker enzymes in plasma and lipid peroxidation in heart tissue. A parallel decline in the levels of ATP (Adenosine triphosphate) and GSH and the activities of glutathione-dependent antioxidant enzymes and antiperoxidative enzymes in heart tissue was also observed. Prior oral administration of glutamine significantly prevented isoprenaline-induced adverse effects and maintained myocardial antioxidant status at near normal status. The cardioprotective effect of glutamine is probably related to a strengthening of the myocardial membrane by its membrane stabilizing action, or to a counteraction of free radicals by its antioxidant property, or to its ability to maintain near to normal status the activities of free radical scavenging enzymes and the level of GSH, which protect myocardial membrane against oxidative damage by decreasing lipid peroxidation.     

Antioxidant potential of vitamins A, E and C in modulating oxidative stress in rat brain

Background: Stress is known to affect synaptic plasticity, dendritic morphology and induces neurotoxic damage in humans, probably through generation of free radicals. Both ex vivo antioxidant vitamins and in vivo free radical scavenging enzymes exist. In the present study, restraint stress induced pro-oxidant status of rat brain was evaluated in terms of measurement of glutathione (GSH), lipid peroxidation (thiobarbituric acid reactive substances, TBARS) and free radical scavenging enzymes activities. The efficacy of antioxidant vitamins A, E and C alone and in combination was also evaluated in modulating inherent antioxidant system in stressed rats. Methods: Rats were treated with vit A, E and C alone (15 mg/kg of body weight) and in combination vitamins (E and C) prior to and after 6 h of restraint stress exposure. Both nonstressed and stressed rats were handled simultaneously. Pro-oxidant status of brain tissue was evaluated by determining the levels of GSH, TBARS and activities of superoxide dismutase (SOD), glutathione-S-transferase (GST) and catalase (CAT). Results: Restraint stress induced a decrease in the level of GSH and the activities of SOD, GST and catalase, while the levels of TBARS were found elevated. Both pre-stress and post-stress vitamin treatments (either alone or combined) resulted in alteration of these parameters towards their controls values with a relative dominance by latter. Vitamin E was found most effective in restoring inherent antioxidant system, no additive effect was observed in combined vitamin treatment as expected. Conclusion: Immobilization of rats generated oxidative stress in rat brain, by decreasing the activities of SOD, GST, catalase and glutathione levels, while increasing the lipid peroxidation. Post stress vitamin E treatment was found most effective than vitamins A and C in enhancing the levels of glutathione and activities of SOD, GST and catalase and decreasing lipid peroxidation. Thus vitamin E can be given as a nutritional supplement for scavenging free radical generated in the brain tissues in order to reduce oxidative stress.     

Oxidant/antioxidant parameters and their relationship with chemotherapy in Hodgkin's lymphoma

This study investigated changing levels of serum oxidant/antioxidant with chemotherapy and their relation to treatment in 34 Hodgkin's lymphoma patients. The patient population consisted of 19 males and 15 females. Mean age was 30.41 +/- 12.08 years. All patients received the adriamycin, bleomycin, vincristine and dexamethasone (ABVD) treatment protocol. Blood samples were taken before treatment, and on days 1 and 7 during treatment for measurement of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), malondialdehyde (MDA), nitric oxide (NO) and enzyme activities. After ABVD treatment, mean free radical levels were increased and antioxidant levels were significantly decreased in the serum. ABVD treatment results in an increase of free radical levels and a decrease of antioxidant levels in the serum of patients with Hodgkin's lymphoma.     

The effects of hyperbaric oxygen treatment on oxidant and antioxidants levels during liver regeneration in rats

The effects of hyperbaric oxygen (HBO) therapy on oxidant/antioxidant metabolism are controversial and its effects on hepatic regeneration are not known. In this study, we investigated a possible beneficial effect of HBO therapy on oxidant and antioxidants levels during liver regeneration. To conduct this study, seventy percent hepatectomy was performed on forty-eight Spraggue-Dawley rats and the rats were divided into two equal groups: HBO-treated group and untreated group (non-HBO group). We determined the levels of malondialdehyde (MDA), an oxidative stress marker, and the levels of antioxidant enzymes/reagents, including glutathione (GSH), superoxide dismutase (SOD) activity, copper (Cu) and zinc (Zn), in the remnant liver samples. We also measured mitotic index (MI) and proliferating cell nuclear antigen (PCNA) levels to assess the degree of liver regeneration. HBO treatment significantly decreased MDA levels, whereas it increased SOD activity, GSH and Zn levels. In contrast, Cu levels were lower in the HBO-treated livers than the levels in the untreated remnant livers. The effect of HBO treatment may be mediated by the suppression of certain enzymes that are responsible for lipid peroxidation. In addition, HBO treatment may induce the production of antioxidant enzymes/reagents by remnant liver tissues. The HBO-treated rats maintained their body weights but the untreated rats lost body weights. HBO treatment also increased MI and PCNA levels, indicating HBO treatment enhances liver regeneration. These results indicate that HBO treatment has beneficial effects on liver regeneration by decreasing MDA and by increasing antioxidant activities. We therefore suggest that HBO therapy may be useful after liver resection.     

Clinical

Objective: To investigate the oxidative state of glutathione and glutathione peroxidase (GSH-Px'), glutathione reductase (GSSG-R), and glucose-6-phosphate dehydrogenase (G-6-PD) levels in patients with chronic renal failure (CRF) and controls.

Results: Erythrocyte GSH levels of patients were decreased, but GSSG was not significantly different from that of controls. Also, plasma GSH levels were not different, although GSSG was increased. GSSG/GSH ratios in erythrocyte and plasma were significantly higher in CRF patients. Erythrocyte GSSG-R activity was high, but G-6-PD and GPX were low.

Conclusions: The findings suggest that: 1. Low GSH is related to decreased G-6-PD activities. 2. The reduction of peroxides with GPX are decreased by low GSH and low GPX activity. 3. GSSG may react with hemoglobin and causes protein aggregation in erythrocytes. These alterations cause hemolysis and could play a role in the pathogenesis of anemia in hernodialyzed patients.     

Glutathione peroxidase, glutathione reductase, Cu-Zn superoxide dismutase activities, glutathione, nitric oxide, and malondialdehyde concentrations in serum of patients with chronic lymphocytic leukemia

BACKGROUND: Chronic lymphocytic leukemia (CLL) is a rare neoplasm that comprises a substantial proportion of all leukemias in middle-aged persons and is the most common type among elderly persons. The major causes are not known nor is there a detailed understanding about how the elusive origin(s) may relate to clinical expression, basic biological mechanisms, or pathogenesis. METHODS: Glutathione peroxidase (GSH-Px), glutathione reductase (GRD), Cu-Zn superoxide dismutase (Cu-Zn SOD) activities, glutathione (GSH), nitric oxide (NO(*), and malondialdehyde (MDA) concentrations were measured in serum of patients with CLL and a healthy control group. RESULTS: Serum GSH-Px, Cu-Zn SOD activities, GSH concentration were lower in patients with CLL while serum NO(*) and MDA concentrations were higher in these patients compared with the control group. Serum GRD activity was not statistically significant in patients with CLL compared with the control. However, there was no statistically significant difference in the parameters on the basis of stages in these patients. Serum GSH concentration negatively correlated with serum MDA (r=30.63, p<0.05) and NO(*) concentrations (r=0.72, p<0.05) in patients with advanced stage (III+IV). However, no other correlation could be found among the parameters in healthy controls and patients with CLL CONCLUSIONS: There is significant changes in antioxidant defense system in CLL cases, which may lead to enhanced action of oxygen radical, resulting in lipid peroxidation.     

Susceptibility of glutatione and glutathione-related antioxidant activity to hydrogen peroxide in patients with type 2 diabetes: effect of glycemic control

OBJECTIVES: The aim of the present study was to examine the susceptibility of glutathione (GSH) and glutathione related antioxidant enzymes to oxidation in type 2 diabetic patients with and without glycemic control. DESIGN AND METHODS: Erythrocyte glutathione level and activities of glutathione peroxidase (G-Px), glutathione reductase (G-Red) and glutathione S-transferase (GST) in controls, well controlled and poorly controlled type 2 diabetics were measured by spectrophotometric assays before and after the incubation in vitro with H2O2. RESULTS: GSH level, G-Px and G-Red activities decreased but GST activity increased in the erythrocytes from all the groups after the incubation with H2O2. Percentage of decrease in GSH was independent from glycemic control, whereas the percentage of decreases in G-Px and G-Red was related to glycemic control. The percentage of increase in GST was found to be independent from diabetes. CONCLUSIONS: GSH and GSH-related antioxidant enzymes in human erythrocytes are susceptible to oxidation, particularly, G-Px and G-Red which were found to be more susceptible to oxidation in erythrocytes from poorly controlled type 2 diabetic patients.     

Oxidative stress in polycystic ovary syndrome and its contribution to the risk of cardiovascular disease

OBJECTIVES: To determine oxidant and antioxidant status in women with polycystic ovary syndrome (PCOS) and its contribution to the risk of cardiovascular disease. DESIGN AND METHODS: 27 women with PCOS were compared with regard to oxidant and antioxidant status with 18 age- and body mass index (BMI)-matched healthy. Oxidant status was evaluated by determination of erythrocyte malondialdehyde (MDA) concentration, while antioxidant status was evaluated by determination of erythrocyte reduced glutathione (GSH) concentration, and glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities. Area under curve (AUC) for glucose, AUC for insulin and the insulin sensitivity index (ISI) were calculated from two-hour OGTT. RESULTS: Women with PCOS were found to have higher AUC for glucose (p = 0.01), AUC for insulin (p < 0.001), MDA level (p = 0.009) and SOD activity (p = 0.04), and lower ISI (p < 0.001) and GSH level (p = 0.03) than the controls. In correlation analysis, a significant relationship was found between MDA levels and age (p < 0.01), BMI (p < 0.001), waist-to-hip ratio (p < 0.01), systolic and diastolic blood pressures (both p < 0.05), AUCs for glucose and insulin (both p < 0.05), ISI (r = -0.42, p < 0.05) and triglyceride (p < 0.01). CONCLUSIONS: An increase in oxidant status was found in women with PCOS, and this increase was related to central obesity, age, blood pressure, serum glucose, insulin and triglyceride levels and insulin resistance. In contrast, antioxidant status was observed to be insufficient. These findings suggest that increased oxidative stress may contribute to the increased risk of cardiovascular disease in women with PCOS.     

抗氧化剂预防低血糖所致肌肉损伤的研究

目的 探讨低血糖状态下血浆和组织中谷胱甘肽含量的变化以及还原型谷胱甘肽（GSH）对血清酶活性的抑制作用。方法 静脉注射胰岛素诱发低血糖，并持续60min，然后输注葡萄糖解除低血糖。结果发现诱发低血糖后6h，血浆GTSH，氧化型谷胱甘肽（GSSG），谷胱甘肽总量（TGSH）及GSSG/TGSH比值均明显升高，肝脏GSH和TGSH明显减少，心肌和骨骼肌CSSG和GSSG/TGSH比值明显增高，同时伴有血清酶（ALT，AST，LDH，CK）活性升高，预先注射CSH后诱发低血糖组，血浆GSSG和GSSG/TGSH比值明显下降，并抑制了血清酶的活性。结论 低血糖所致的血清酶活性的升高与体内谷胱甘肽氧化还原状态的改变有关。补充抗氧化剂GSH可以预防低血糖所致的肌肉损伤。