Effect Of Exogenous Glutathione Research Articles

Glutathione and Proline Attenuates Injury Induced by Boron Toxicity in Wheat

Given the increasing importance of boron (B) toxicity, the present study investigates the roles of glutathione (20 mM, GSH) and proline (20 mM) in the improvement of wheat (Triticum aestivum cv. Altındane) resistance to B toxicity (10 mM B). The plants were raised in hydroponic culture with control, B toxicity, B+glutathione, B+proline, glutathione and proline. B+glutathione and B+proline resisted the detrimental influences of B toxicity on the root and shoot lengths, the total chlorophyll, and phenolic contents. B toxicity increased superoxide radicals (O2.-), hydrogen peroxide (H2O2), lipid peroxidation (MDA), and proline contents while B+glutathione and B+proline applications diminished the mentioned parameters with the exception of the proline content. Individual B toxicity and combined B+glutathione and B+proline applications increased generally total ascorbic acid and glutathione levels in the wheat while the B+proline application decreased GSH content. The B toxicity decreased superoxide dismutase, catalase and guaiacol peroxidase activities in compared with control with the exception of the ascorbate peroxidase activity. Exogenous glutathione and proline augmented all enzyme activities in the wheat exposed to B toxicity. As a result, it can be suggested that glutathione and proline mitigates B toxicity; by preventing oxidative damage in the membrane, by increasing enzymatic and non-enzymatic antioxidant and by decreasing O2.-, H2O2, and MDA contents. Glutathione is generally more effective than proline in mitigating the above detrimental effects of B toxicity. The datum submitted in the current work are significant and the first to indicate that effects of exogenous glutathione and proline in improving a culture plant strength to B toxicity.

Effect of Changes in the Redox Status on Biofilm Formation in Escherichia coli.

Changes in the redox balance in the medium and in Escherichia coli cells significantly affect the ability of bacteria to form biofilms. An increase in the level of aeration in the culture of wild-type bacteria led to a 3-fold decrease in the mass of biofilms. Mutants lacking components of the glutathione and thioredoxin redox systems, as well as transporters involved in the transmembrane cycling of glutathione, demonstrated increased biofilm formation ability. The effect of exogenous glutathione on biofilm formation depended on the culturing conditions. The addition of 0.1-1 mM Trolox (a water-soluble analog of vitamin E) was accompanied by a 30-40% reduction in biofilm formation.

Application of exogenous glutathione decreases chromium translocation and alleviates its toxicity in soybean (Glycine max L.)

Chromium is considered one of the most severe toxic elements affecting agriculture. Soybean seedlings under chromium stress were treated with glutathione and buthionine sulfoximine. The effects of exogenous glutathione on the physiological effects of two different chromium-resistant soybean seedlings and the expression levels of expression levels related genes were studied. This study tested the seedling weight and SPAD values, detected enzymatic antioxidants (i.e., superoxide dismutase, peroxidase, catalase, catalase, ascorbate peroxidase), and non-enzymatic antioxidants (i.e., glutathione, proline, soluble sugars, and soluble phenols) that attenuate chromium-induced reactive oxygen species, and quantified several genes associated with glutathione-mediated chromium stress. The results showed that exogenous glutathione could improve the physiological adaptability of soybean seedlings by regulating photosynthesis, antioxidant, and related enzyme activities, osmotic system, the compartmentalization of ion chelation, and regulating the transcription level of related genes, thereby increasing the chromium accumulation of soybean seedlings, enhancing the tolerance of chromium stress, and reducing the toxicity of chromium. Overall, the application of glutathione alleviates chromium toxicity in soybeans, and this strategy may be a potential farming option for soybean bioremediation in chromium-contaminated soils.

Exogenous Glutathione Alleviation of Cd Toxicity in Italian Ryegrass (Lolium multiflorum) by Modulation of the Cd Absorption, Subcellular Distribution, and Chemical Form.

Subcellular fractions and the chemical forms of cadmium (Cd) reflect its level of toxicity to plants; however, these effects of exogenous glutathione (GSH) are poorly understood. We exposed two Italian ryegrass (Lolium multiflorum) cultivars (IdyII and Harukaze) to 50 µM Cd or 200 µM GSH to investigate the effect of GSH on the Cd uptake, subcellular compartments, and chemical forms. Cd significantly inhibited the plant growth, while GSH supplementation decreased this inhibition. The application of GSH significantly improved the Cd concentration in the roots but reduced that in the shoots and decreased the Cd translocation from root to shoot. The Cd concentration of the root in the cell wall was increased while the concentration in the soluble fraction was decreased when supplied with GSH. The inorganic form (80% ethanol for Cd extraction) in the roots was significantly reduced when treated with GSH. The Cd form extracted by 2% acetic acid (HAC) with low toxicity and immobility were greatly increased. In leaves, the application GSH decreased in any form of Cd form extracted. In conclusion, exogenous GSH decreased the translocation of Cd and alleviated Italian ryegrass Cd toxicity by accumulating more Cd in the root cell wall and immobilizing more Cd in lower toxicity fractions.

Effects of exogenous glutathione on antioxidant system of cucumber seedlings under cadmium stress

With the development of social economy, environmental protection has become a hot topic. Excessive emissions of agricultural chemicals increase the accumulation of the heavy metal cadmium (Cd) in soil. When plants are stressed by high concentrations of heavy metals, their antioxidant capacity and detoxification capacity will decrease, which will lead to damage the cell mechanism of plants. Glutathione (GSH), as an important water-soluble antioxidant in the organism, can enhance plant resistance in stress. This study used cucumber seedlings as test material, using hydroponics, to research the effects of exogenous GSH on antioxidant system under Cd stress. The study showed that exogenous GSH could enhance the antioxidant capacity of cucumber leaves under Cd stress and increase the activity of SOD and POD, and reduce the content of MDA. However, the contents of reduced GSH and GSSH were reduced when exogenous glutathione was applied under Cd stress.

Effects of exogenous glutathione and cysteine on growth, lead accumulation, and tolerance of Iris lactea var. chinensis

Effects of exogenous reduced glutathione (GSH) and cysteine (Cys) on growth, lead (Pb) accumulation, and nonprotein thiol (NPT) contents of Iris lactea var. chinensis under 100 and 500 mg L(-1) Pb stress were studied. Our results showed that 500 mg L(-1) Pb stress caused a dramatical decline in fresh weights, while the reduction of aboveground biomass was alleviated by exogenous GSH and Cys even though keeping higher Pb contents in roots and shoots. Exogenous GSH and Cys could enhance Pb accumulation in the shoots and roots compared with single Pb treatment. The promoting effect of GSH to Pb accumulation was larger than the effect of Cys, and the Pb contents in the shoots and roots treated with 500 mg L(-1) Pb + GSH reached 1,712 and 14,603 mg kg(-1), about 4.19 and 2.78 times of single 500 mg L(-1) Pb treatment, respectively. Microscopic imaging of Pb in roots and leaves showed that higher intensive fluorescence was observed in cell wall of root epidermis, stele, vascular tissues of the roots, and sclerenchyma cells of leaves treated with 500 mg L(-1) Pb + GSH and treated with 500 mg L(-1) Pb + Cys. Exogenous GSH had an apparent promoting effect on root and shoot GSH synthesis, while exogenous Cys reduced the synthesis of cellular GSH in shoot and increased Cys contents. Pb only induced the synthesis of phytochelatin (PC)2 in roots, and the PC2 content declined in GSH- and Cys-treated plant roots. These results suggested that GSH synthesis was a more effective approach to improve Pb accumulation and translocation of I. lactea var. chinensis. Further analysis of protein expression in plants by exogenous GSH and buthionine sulfoximine (BSO) application showed that the proteins regulated by GSH and BSO may constitute various enzymes involved in GSH biosynthesis and play certain roles in Pb accumulation and tolerance of I. lactea var. chinensis.

Mitigation effects of exogenous glutathione on the growth of Dianthus chinensis seedlings under Cd stress

Aims The objective was to investigate exogenous glutathione(GSH) mitigation effects of Cadmium(Cd) toxicity on ground cover plants.Methods A greenhouse pot experiment was conducted to explore the effects of spraying different concentrations(0, 20, 40, 60, 80 and 100 mg·L–1) exogenous GSH on Dianthus chinensis seedlings exposed to 50 mg·kg–1Cd in the soil.Important findings 50 mg·kg–1Cd significantly inhibited the growth of D. chinensis seedlings; however, a range of concentrations of sprayed exogenous GSH significantly relieved Cd stress on D. chinensis seedlings. Sprayed D. chinensis seedlings had increased activities of the catalase(CAT), peroxidase(POD), ascorbate peroxidase(APX), monodehydroascorbate reductase(MDAR), dehydroascorbate reductase(DHAR) and glutathione reductase(GR), as well as increased ascorbic acid(AsA) and GSH contents, biomass, plant height and number of tillers. There were decreases in malondialdehyde(MDA), cell membrane permeability, Cd contents, O2·–production rates and accumulated amount of H2O2. However, with increased exogenous GSH concentration, there was a downward trend in mitigation effects. Considering all factors, the mitigation effects were maximized by spraying55–65 mg·L–1exogenous GSH.

Effect of Exogenous Glutathione and Selenium on Cadmium-Induced Changes in Cadmium and Mineral Concentrations and Antioxidative Metabolism in Maize Seedlings

Effect of Exogenous Glutathione and Selenium on Cadmium-Induced Changes in Cadmium and Mineral Concentrations and Antioxidative Metabolism in Maize Seedlings

Glutathione-Mediated Alleviation of Chromium Toxicity in Rice Plants

A hydroponic experiment was conducted to determine the possible effect of exogenous glutathione (GSH) in alleviating chromium (Cr) stress through examining plant growth, chlorophyll contents, antioxidant enzyme activity, and lipid peroxidation in rice seedlings exposed to Cr toxicity. The results showed that plant growth and chlorophyll content were dramatically reduced when rice plants were exposed to 100 μM Cr. Addition of GSH in the culture solution obviously alleviated the reduction of plant growth and chlorophyll content. The activities of some antioxidant enzymes, including superoxide dismutase, catalase (CAT) and glutathione reductase in leaves, and CAT and glutathione peroxidase in roots showed obvious increase under Cr stress. Addition of GSH reduced malondialdehyde accumulation and increased the activities of these antioxidant enzymes in both leaves and roots, suggesting that GSH may enhance antioxidant capacity in Cr-stressed plants. Furthermore, exogenous GSH caused significant decrease of Cr uptake and root-to-shoot transport in the Cr-stressed rice plants. It can be assumed that GSH is involved in Cr compartmentalization in root cells.

Effect of glutathione on canine myocardial ischaemia without reperfusion.

The present study was to evaluate the effect of exogenous glutathione on myocardial damage resulting from permanent (no reperfusion) coronary ligation (3 or 6 h) in anaesthetized dogs. Haemodynamics, infarct size and myocardial glutathione content were determined. Erythrocyte superoxide dismutase (SOD) activity was also determined in coronary venous blood samples. Glutathione was administered by the intraperitoneal route, 100 mg kg-1 as initial dose given 5 min before coronary ligation, and successive doses of 25 mg kg-1 every 40 min throughout the study period. Saline-treated dogs showed myocardial infarction, a decrease in myocardial glutathione content, and a transient increase in SOD activity. Three hours occlusion in glutathione-treated dogs resulted in a small reduction of infarct size, and no changes in myocardial glutathione content and SOD activity. By contrast, administration of glutathione failed to reduce infarct size and failed to prevent myocardial glutathione decrease in dogs subjected to 6 h occlusion. These results indicate that exogenous glutathione is of minor beneficial effect for myocardial damage resulting from permanent coronary occlusion and suggest that endogenous glutathione has a limited role in protecting against myocardial ischaemia without reperfusion.

Effects of exogenous glutathione on arsenic burden and NO metabolism in brain of mice exposed to arsenite through drinking water

Chronic exposure to inorganic arsenic (iAs) is associated with neurotoxicity. Studies to date have disclosed that methylation of ingested iAs is the main metabolic pathway, and it is a process relying on reduced glutathione (GSH). The aim of this study was to explore the effects of exogenous GSH on arsenic burden and metabolism of nitric oxide (NO) in the brain of mice exposed to arsenite via drinking water. Mice were exposed to sodium arsenite through drinking water contaminated with 50 mg/L arsenic for 4 weeks and treated intraperitoneally with saline solution, 200 mg/kg body weight (b.w), 400 mg/kg b.w, or 800 mg/kg b.w GSH, respectively, at the 4th week. Levels of iAs, monomethylarsenic acid, and dimethylarsenic acid (DMAs) in the liver, blood, and brain were determined by method of hydride generation coupled with atomic absorption spectrophotometry. Activities of nitric oxide synthase (NOS) and contents of NO in the brain were determined by colorimetric method. Compared with mice exposed to arsenite alone, administration of GSH increased dose-dependently the primary and secondary methylation ratio in the liver, which caused the decrease in percent iAs and increase in percent DMAs in the liver, as a consequence, resulted in significant decrease in iAs levels in the blood and total arsenic levels in both blood and brain. NOS activities and NO levels in the brain of mice in iAs group were significantly lower than those in control; however, administration of GSH could increase significantly activities of NOS and contents of NO. Findings from this study suggested that exogenous GSH could promote both primary and secondary arsenic methylation capacity in the liver, which might facilitate excretion of arsenicals, and consequently reduce arsenic burden in both blood and brain and furthermore ameliorate the effects of arsenicals on NO metabolism in the brain.

Effects of Exogenous Glutathione on the Quality of Chilled Bull Semen

Glutathione (GSH) at concentrations of 0.0 (control), 0.5, 1.0, 2.0 and 3.0 mM was added to chilled bull semen to determine its effects on the keeping quality of semen used for artificial insemination (AI). The semen was preserved with egg yolk citrate extender. All samples were stored at 4-8 degrees C for 5 days. Sperm motility and proportion of abnormal acrosome were assessed daily. Sperm motility was significantly (p < 0.01) higher in the semen treated with 0.5 mM glutathione than in untreated semen on each day. The optimum sperm motility (>or=50%) for AI was retained significantly (p < 0.01) for 3 days in 0.0, 0.5, 1.0 and 2.0 mM glutathione treated semen, whereas in 0.3 mM glutathione-treated semen, sperm motility was 46.8% for 3 days. Acrosomal damage was significantly (p < 0.01) reduced after addition of 0.5 mM GSH in the preserved semen. Bull semen can be preserved in chilled condition for 5 days with 0.5 mM GSH with sperm motility above 40% and 12% acrosome abnormality.

Short-chain 3-ketoceramides, strong apoptosis inducers against human leukemia HL-60 cells

Ceramides act as a second messenger of the apoptotic signaling process. The allylic alcohol portion comprising the C-3, C-4, and C-5 carbons is essential for this function. The suggestion has been made that this alcohol moiety is oxidized in mitochondria to a carbonyl moiety, with the generation of reactive oxygen species. However, there is no established precedent for the apoptotic performance of 3-ketoceramides thus presumed. In this work, we have synthesized three different types of short-chain 3-ketoceramides, that is, (2 S, 4 E)-2-acetylamino-3-oxo-4-octadecen-1-ol ( A), (2 S, 4 E, 6 E)-2-acetylamino-3-oxo-4,6-octadecadien-1-ol ( B), and (2 S, 4 E)-2-acetylamino-1-methoxy-3-oxo-4-octadecene ( C), and demonstrated that these 3-ketoceramides are capable of inducing effective apoptosis in human leukemia HL-60 cells. In particular, the two monoenoic compounds, A and C, are far more powerful than the corresponding alcoholic analogue, N-acetyl- d- erythro-sphingosine. Observations of DNA fragmentation, caspase-3 activation, and cytochrome c release from mitochondria provide substantiated evidence for mitochondrial apoptosis and the effects of exogenous glutathione on these phenomena are also discussed.

The effects of exogenous glutathione on reduced glutathione level, glutathione peroxidase and glutathione reductase activities of rats with different ages and gender after whole-body Γ-irradiation

Age-and gender-related changes on reduced glutathione (GSH) level, glutathione peroxidase (GPx) and glutathione reductase (GR) activities in the liver of rat exposed to different dose of whole-body g-ray irradiation were determined. In addition, the effect of administration of exogenous GSH on endogenous GSH levels, GPx and GR activities was investigated. For this aim, male and female rats aged 1 and 5 moths were divided into two groups as g-ray and g-ray+GSH. Both groups were again divided into four groups as irradiated with 2, 4, 6 and 8 Gy doses. GSH level and GPx activity did not change with age while GR activity was decreased with age. Gender-dependent changes in GPx and GR activities were observed, but GSH values were not affect by sex. GSH levels, GPx and GR activities were not observed dose-associated changes of g-irradiation. GSH level and GPx activity in the 8Gy group were increased by GSH. GR activities of old male rats were found to be increased by glutathione in the 6 and 8Gy groups. These results indicate that radiation and administration of exogenous GSH affect gender-and age-dependent GSH level, GPx and GR activities in the rats.

Effect of exogenous glutathione in medium fertilization to improve blastocyst rates of bovine embryos

Glutathione (C10H17N3O6S) is a tripeptide (γ-Glu-Cys-Gly) widespread in living organism. Glutathione (GSH) at the 5 mM concentration increased the motility and fertility of frozen-thawed sperm. Intracellulair glutathione improved the cleavage rate and embryo development to the blastocyst rate. Research on in vitro embryos production through the implementation of GSH during IVF ( in vitro fertilization) on embryo development has been conducted at the Laboratorium Reproductive of Physiology, Research Institute for Animal Production. Ovaries of beef cattle as source of oocytes were collected from the slaughterhouse in a thermo flask with 350C PBS as medium and transported to the laboratory. The oocytes were fertilized in vitro with selected motile sperm using Percoll gradient (90 and 45%). Ten COCs ( cumulus oocytes complexes ) were transfered to 44 μl of fertilization medium (mTALP) was performed with either 0; 0.25; 0.50; 0.75 and 1.00 mM of glutathione as treatment A, B, C, D and E respectively, and inseminated with 2 μl of capacitated sperm and added 2 μl of heparin and 2 μl of PHE (consisting of 20 μM penicillamine, 10 μM hypotaurine, 1 μM epinephrine). Incubation between sperm and oocytes in the 5% CO2 incubator and RH 90% in fertilization media (TALP) for 20 hours. All zygotes were cultured in modification of CR1aa medium up to blastocyst and were fed serum 5 μl/50μl medium on day 6. Results of this experiment showed that the effect of concentration of glutathione (0, 0.25; 0.50; 0.75 and 1.00 mM) on fertilization medium to the percentage of cleavage rates were 69.35 + 29.40; 79.07 + 13.17; 67.88 + 10.65; 98.10 + 3.30 and 82.62 + 24.19% not significant different (P>0.05) among treatments A, B, C, D dan E respectively.The precentages of morula and blastocyst for treatment D were 50.45 + 42.64% and 31.28 + 24.28%; while 36.55 + 24.13% and 17.74 + 17.86% for treatment E respectively. Key words : Glutathione, in vitro fertilization, oocytes, cleavage

Effect of exogenous glutathione on the in vitro fertilization of bovine oocytes

Increased amounts of reactive oxygen species (ROS) during in vitro culture may cause cytotoxic damage to gametes and embryos. The main purpose of this study was to investigate the effect of glutathione (GSH), a ROS scavenger, supplemented during IVF of bovine oocytes on embryo development using spermatozoa from different bulls. The following experiments were performed: 1) matured COCs were fertilized in the absence or presence of 1 mM GSH using semen from 4 bulls (Bulls A, B, C and D); 2) matured COCs were fertilized in the absence or presence of 1 mM GSH using semen from Bull C to examine sperm penetration, pronuclear formation and apposition; 3) COCs were fertilized with in the presence of either 0,0.1, 1.0 or 10 mM GSH to examine the effect of GSH concentration using sperm from Bull C; 4) concentrations of GSH were measured both in the medium and in the oocytes during IVF. Glutathione at 1mM in IVF medium affected the blastocyst formation, but not the cleavage rate. The effect on blastocyst formation was bull dependent: semen from Bull B and D had a negative, that from Bull C a positive and the one from Bull A no effect. The positive effect of Bull C semen increased the rate of blastocyst formation from 20.1 to 27.3% in control and GSH-treated samples, respectively. The increased rate was due to more zygotes reaching the 8-cell or greater stage by Day 4 after IVF. There was no change in the fertilization or cleavage rates. The GSH was still stable after 18 h incubation in IVF medium, and there was a dose-dependent increase in the GSH concentration in the oocytes. It is concluded that the effect of GSH during IVF on the proportion of blastocysts is dependent on both bull and GSH concentration.

Effect of glutathione administration on hepatic biliary and plasmatic glutathione levels in the rat.

Since the effect of exogenous glutathione (GSH) on overall hepatic GSH homeostasis is not known, the present study investigated the changes in the hepatic, biliary, and plasmatic GSH levels during GSH administration in intact rats. An exteriorized biliary-duodenal fistula was established, and GSH (1 mmol/kg over 2 h) or saline was administered intraperitoneally to rats with or without pretreatment with 5 mmol/kg L-serine borate, an inhibitor of gamma-glutamyltransferase (GGT). Three hours after GSH administration, biliary GSH efflux and bile flow rose from 104.7 +/- 5.6 to 290.6 +/- 8.6 micrograms/ml bile and from 20.2 +/- 1.3 to 30.2 +/- 2.1 microliters/min, respectively; GSH-treated rats also showed increased liver (35%) and posthepatic vein plasma (68%) GSH concentrations compared with controls. By contrast, in rats pretreated with the GGT inhibitor GSH administration appeared to be devoid of any effect, except for a modest biliary GSH increase. This study indicates that significant changes occur in the hepatic GSH homeostasis after intraperitoneal GSH administration. The activity of hepatic GGT, most likely through degradation of circulating GSH, followed by an increase in cysteine availability, seems to account, at least partially, for the reported effects.

The effects of exogenous glutathione and cysteine on oxidative stress induced by ferric nitrilotriacetate

The effects of the antioxidants, glutathione (GSH) and its precursor cysteine (Cys) on oxidative damage induced by ferric nitrilotriacetate (Fe-NTA) were examined. Fe-NTA-associated oxidative stress caused the depletion of renal cellular GSH content. Administration of exogenous GSH and Cys suppressed 8-hydroxydeoxyguanosine (8-OH-dG) formation, an indicator of oxidative DNA damage and nephrotoxicity following Fe-NTA treatment. This suggests that generation of free radicals may be causally involved in oxidative lesion generation. Since lipid peroxidation was found to be inhibited only by GSH and not Cys treatment, this suggests that this effect and the DNA damage might be mediated by different pathways. Fe-NTA-associated oxidative stress in renal tubular cells might thus operate via both intracellular and external space modes.

Effect of exogenous glutathione on tumor progression in the murine skin multistage carcinogenesis model.

Oxidative stress has been suggested to play an integral role in the cancer process. It may be particularly significant during tumor progression, where there is likely to be a large amount of free radicals generated by infiltrating inflammatory cells and dying tumor cells. In order to test this hypothesis, a variety of free radical scavengers and antioxidants were assessed for their ability to inhibit tumor progression. The murine skin multistage carcinogenesis model was used to generate papillomas, which are a population of putative precancerous lesions. Various test agents were applied topically to papillomas in order to determine if they would decrease the incidence of the malignant lesion, squamous cell carcinoma. The agents tested included: reduced glutathione (GSH), butylated hydroxyanisole, vitamin E, copper(II) (3,5-diisopropylsalicylate)2, sodium benzoate, N-acetyl cysteine and disulfiram. Under the conditions of our experiments, only GSH and disulfiram inhibited tumor progression to a significant degree. Additional studies indicated that GSH prevented cancer development in a dose-dependent manner. Another experiment demonstrated that when papillomas received repeated topical applications of diethylmaleate, a GSH-depleting agent, tumor progression was enhanced. Collectively these data suggest that sufficient glutathione levels may be important in preventing cancer formation.

Effect of Exogenous Glutathione, Glutathione Reductase, Chlorine Dioxide, and Chlorite on Osmotic Fragility of Rat Blood In Vitro

Chlorine dioxide (CIO2), chlorite (CIO-2), and chlorate (CIO-3) in drinking water decreased blood glutathione and RBC osmotic fragility in vivo. The osmotic fragility and glutathione content were also studied in rat blood treated with CIO2, CIO-2, CIO-3 in vitro. RBC hemolysis was decreased in rat blood after 30, 60, and 120 minutes by all treatments. The glutathione content expressed as percentage of controls was decreased with incubation time. When CIO2 was added with reduced glutathione (GSH) to the blood, no effect on hemolysis was observed compared to control or to GSH alone at 2 hours, but decreased hemolysis was observed with CIO2 treatment alone. Addition of NADPH alone prevented CIO2 and CIO-2 and CIO-3 from exhibiting hemolysis resistance, while glutathione reductase (GR) and its cofactor (NADPH) increased hemolysis about 1.5–2 fold. Removing GR only resulted in increased resistance to hemolysis with CIO2 or CIO-2. The formation of disulfide bonds between sulfhydryl groups in erythrocytic membranes and hemoglobin, causing precipitation of hemoglobin (yielding apparent resistance to hemolysis) can account for the difference between the hemolysis before and after the addition of GR.