Alteration of glutathione reductase expression in the female reproductive organs during the estrous cycle

Building a Human Ovarian Antioxidant ceRNA Network "OvAnOx": A Bioinformatic Perspective for Research on Redox-Related Ovarian Functions and Dysfunctions

The ovary is a major determinant of female reproductive health. Ovarian functions are mainly related to the primordial follicle pool, which is gradually lost with aging. Ovarian aging and reproductive dysfunctions share oxidative stress as a common underlying mechanism. ROS signaling is essential for normal ovarian processes, yet it can contribute to various ovarian disorders when disrupted. Therefore, balance in the redox system is crucial for proper ovarian functions. In the present study, by focusing on mRNAs and ncRNAs described in the ovary and taking into account only validated ncRNA interactions, we built an ovarian antioxidant ceRNA network, named OvAnOx ceRNA, composed of 5 mRNAs (SOD1, SOD2, CAT, PRDX3, GR), 10 miRNAs and 5 lncRNAs (XIST, FGD5-AS1, MALAT1, NEAT1, SNHG1). Our bioinformatic analysis indicated that the components of OvAnOx ceRNA not only contribute to antioxidant defense but are also involved in other ovarian functions. Indeed, antioxidant enzymes encoded by mRNAs of OvAnOx ceRNA operate within a regulatory network that impacts ovarian reserve, follicular dynamics, and oocyte maturation in normal and pathological conditions. The OvAnOx ceRNA network represents a promising tool to unravel the complex dialog between redox potential and ovarian signaling pathways involved in reproductive health, aging, and diseases.

Histological, immunohistochemical and serological investigations of the ovary during follicular phase of estrous cycle in Saidi sheep

BACKGROUND

Saidi sheep are the most abundant ruminant livestock species in Upper Egypt, especially in the Assiut governorate. Sheep are one of the most abundant animals raised for food in Egypt. They can convert low-quality roughages into meat and milk in addition to producing fiber and hides therefore; great opportunity exists to enhance their reproduction. Saidi breed is poorly known in terms of reproduction. So this work was done to give more information on some hormonal, oxidative, and blood metabolites parameters in addition to histological, histochemical and immunohistochemical investigations of the ovary during follicular phase of estrous cycle. The present study was conducted on 25 healthy Saidi ewes for serum analysis and 10 healthy ewes for histological assessment aged 2 to 5 years and weighted (38.5 ± 2.03 kg).

RESULTS

The follicular phase of estrous cycle in Saidi sheep was characterized by the presence of ovarian follicles in different stages of development and atresia in addition to regressed corpus luteum. Interestingly, apoptosis and tissue oxidative markers play a crucial role in follicular and corpus luteum regression. The most prominent features of the follicular phase were the presence of mature antral (Graafian) and preovulatory follicles as well as increased level of some blood metabolites and oxidative markers. Here we give a new schematic sequence of ovarian follicles in Saidi sheep and describing the features of different types. We also clarified that these histological pictures of the ovary was influenced by hormonal, oxidative and blood metabolites factors that characterizes the follicular phase of estrous cycle in Saidi sheep.

CONCLUSION

This work helps to understanding the reproduction in Saidi sheep which assist in improving the reproductive outcome of this breed of sheep. These findings are increasingly important for implementation of a genetic improvement program and utilizing the advanced reproductive techniques as estrous synchronization, artificial insemination and embryo transfer.

2-Hydroxy-4-Methylselenobutanoic Acid Promotes Follicle Development by Antioxidant Pathway

Selenium (Se) is assumed to promote the follicle development by attenuating oxidative stress. The current study was developed to evaluate the effects of dietary 2-hydroxy-4-methylselenobutanoic acid (HMSeBA) supplementation on the follicle development in vivo and on the function of ovarian granulosa cells (GCs) in vitro. Thirty-six gilts were randomly assigned to fed control diet (CON), Na₂SeO₃ diet (0.3 mg Se/kg) or HMSeBA diet (0.3 mg Se/kg). The results showed that HMSeBA and Na₂SeO₃ supplementation both increased the total selenium content in liver and serum compared with control, while HMSeBA increased the total selenium content in liver compared with Na₂SeO₃ group. HMSeBA tended to increase the total selenium content in ovary compared with control. HMSeBA and Na₂SeO₃ supplementation both increased the weight of uteri in gilts at the third estrus. Moreover, HMSeBA supplementation down-regulated the gene expression of growth differentiation factor-9 (GDF-9) and bone morpho-genetic protein-15 (BMP-15) in cumulus-oocyte complexes (COCs). HMSeBA supplementation decreased malondialdehyde (MDA) content in serum, liver and ovary, increased activity of T-AOC in liver, TXNRD in ovary and GPX in serum, liver and ovary, while up-regulated the liver GPX2, SOD1 and TXNRD1, ovarian GPX1 gene expression. In vitro, HMSeBA treatment promoted GCs' proliferation and secretion of estradiol (E₂). HMSeBA treatment increased the activity of T-AOC, T-SOD, GPX, TXNRD and decreased MDA content in GCs in vitro. Meanwhile, HMSeBA treatment up-regulated SOD2 and GPX1 gene expression in GCs in vitro. In conclusion, HMSeBA supplementation is more conducive to promoting follicle development by antioxidant pathway.

Hulless Black Barley as a Carrier of Probiotics and a Supplement Rich in Phenolics Targeting Against H2O2-Induced Oxidative Injuries in Human Hepatocarcinoma Cells

Lactic acid bacteria can provide benefits to human beings and transform phenolic substances to improve their potential functionality. It was of interest to develop black barley as a carrier of probiotics and nutraceutical supplement rich in more antioxidants. Due to fermentation, bacterial counting and free phenolic content in black barley increased to 9.54 ± 0.22 log cfu/mL and 5.61 ± 0.02 mg GAE/mL, respectively. Eleven phenolic compounds, including nine isoflavones and two nitrogenous compounds were characterized using UPLC-QTOF-MS, among which epicatechin, hordatine, and pelargonidin aglycone were largely enriched. Moreover, free phenolic extracts from fermented barley (F-BPE) played a greater role in scavenging DPPH radicals, reducing Fe3+ to Fe2+, and increasing oxygen radical absorbance capacity, compared phenolic extracts from unfermented barley [UF-BPE (1.94-, 1.71-, and 1.35-fold at maximum for F-BPE vs. UF-BPE, respectively)]. In hepatocarcinoma cells, F-BPE also better inhibited ROS production and improved cell viability, cell membrane integrity, SOD activity, and non-enzymatic antioxidant GSH redox status (2.85-, 3.28-, 2.05-, 6.42-, and 3.99-fold at maximum for F-BPE vs. UF-BPE, respectively).

Antioxidants Present in Reproductive Tract Fluids and Their Relevance for Fertility

Nowadays, infertility is classified as a disease of the reproductive system. Although it does not compromise the life of the individual, it can have detrimental effects on the physiological and psychological health of the couple. Male fertility evaluation is mainly focused on the analysis of sperm parameters. However, the ejaculated fluid is also composed of seminal plasma, and the study of this fluid can provide crucial information to help in the assessment of male fertility status. Total antioxidant capacity of the seminal plasma has been positively correlated with the fertility of men. Moreover, evidence highlights to a similar importance as that of female reproductive tract fluid antioxidant capabilities and female fertility. Herein, we describe the functions of seminal plasma and female reproductive tract fluids, as well as their main antioxidant components and their relationships with fertility outcomes. Additionally, this review contains the most up to date information regarding the mechanisms of the interaction between the male and the female reproductive fluids and the importance of proper antioxidant capacity for fertilization.

Developmental programming: intrauterine caloric restriction promotes upregulation of mitochondrial sirtuin with mild effects on oxidative parameters in the ovaries and testes of offspring

According to the developmental origins of health and disease (DOHaD) hypothesis, changes in the maternal environment are known to reprogram the metabolic response of offspring. Known for its redox modulation, caloric restriction extends the lifespan of some species, which contributes to diminished cellular damage. Little is known about the effects of gestational caloric restriction, in terms of antioxidant parameters and molecular mechanisms of action, on the reproductive organs of offspring. This study assessed the effects of moderate (20%) caloric restriction on redox status parameters, molecular expression of sirtuin (SIRT) 1 and SIRT3 and histopathological markers in the ovaries and testes of adult rats that were subjected to gestational caloric restriction. Although enzyme activity was increased, ovaries from female pups contained high levels of oxidants, whereas testes from male pups had decreased antioxidant enzyme defences, as evidenced by diminished glyoxalase I activity and reduced glutathione content. Expression of SIRT3, a deacetylase enzyme related to cellular bioenergetics, was increased in both ovaries and testes. Previous studies have suggested that, in ovaries, diminished antioxidant metabolism can lead to premature ovarian failure. Unfortunately, there is little information regarding the redox profile in the testis. This study is the first to assess the redox network in both ovaries and testes, suggesting that, although intrauterine caloric restriction improves molecular mechanisms, it has a negative effect on the antioxidant network and redox status of reproductive organs of young adult rats.

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.

The Role of Antioxidant Enzymes in the Ovaries

Proper physiological function of the ovaries is very important for the entire female reproductive system and overall health. Reactive oxygen species (ROS) are generated as by-products during ovarian physiological metabolism, and antioxidants are indicated as factors that can maintain the balance between ROS production and clearance. A disturbance in this balance can induce pathological consequences in oocyte maturation, ovulation, fertilization, implantation, and embryo development, which can ultimately influence pregnancy outcomes. However, our understanding of the molecular and cellular mechanisms underlying these physiological and pathological processes is lacking. This article presents up-to-date findings regarding the effects of antioxidants on the ovaries. An abundance of evidence has confirmed the various significant roles of these antioxidants in the ovaries. Some animal models are discussed in this review to demonstrate the harmful consequences that result from mutation or depletion of antioxidant genes or genes related to antioxidant synthesis. Disruption of antioxidant systems may lead to pathological consequences in women. Antioxidant supplementation is indicated as a possible strategy for treating reproductive disease and infertility by controlling oxidative stress (OS). To confirm this, further investigations are required and more antioxidant therapy in humans has to been performed.

Exogenous phospholipids supplementation improves growth and modulates immune response and physical barrier referring to NF-κB, TOR, MLCK and Nrf2 signaling factors in the intestine of juvenile grass carp (Ctenopharyngodon idella)

This study was conducted to investigate the effects of dietary phospholipids (PL) on the growth performance, intestinal enzyme activity and immune response and intestinal physical barrier of juvenile grass carp (Ctenopharyngodon idella). A total of 1080 juvenile grass carp with an average initial weight of 9.34 ± 0.03 g were fed six semi-purified diets containing 0.40% (unsupplemented control group), 1.43%, 2.38%, 3.29%, 4.37% and 5.42% PL for 2 months. Results indicated that 3.29% PL increased lysozyme (LZ) and acid phosphatase (ACP) activities and complement component 3 (C3) content (P < 0.05), up-regulated the mRNA relative expression levels of interleukin 10, transforming growth factor β1 (TGF-β1), inhibitor protein κBα (IκBα), target of rapamycin (TOR) and casein kinase 2 (CK2) (P < 0.05), and down-regulated tumor necrosis factor α (TNF-α), interleukin 1β, nuclear factor κB p65 (NF-κB p65), IκB kinase β (IKKβ) and IκB kinase γ (IKKγ) mRNA relative expression levels (P < 0.05) in the intestine, suggesting that optimum PL could improve fish intestinal immunity. In addition, 3.29% PL increased the activities of anti-superoxide anion (ASA), anti-hydroxyl radical, copper/zinc superoxide dismutase (SOD1), glutathione peroxidase (GPx) and glutathione reductase (GR), the content of glutathione (P < 0.05), and the mRNA relative expression levels of occludin, zonula occludens 1 (ZO-1), claudin 3, claudin 12, claudin b, claudin c, SOD1, GPx, GR and NF-E2-related factor 2 (Nrf2) and decreased malondialdehyde (MDA), protein carbonyl (PC) and ROS content (P < 0.05), the mRNA relative expression levels of Kelch-like-ECH-associated protein 1a (Keap1a), myosin light chain kinase (MLCK) and p38 mitogen-activated protein kinase (p38 MAPK) in the intestine, indicating that the optimum PL could improve fish intestinal physical barrier. Finally, based on the PWG, C3 content in the DI, ACP activity in the DI, intestinal PC content and intestinal ASA activity, the optimal dietary PL levels for juvenile grass carp (9.34-87.50 g) were estimated to be 3.46%, 3.79%, 3.93%, 3.72%, and 4.12%, respectively.

Modulation of antioxidant systems by subchronic exposure to the aqueous extract of leaves from Achillea millefolium L. in rats

We determined the effects of subchronic exposure to aqueous extract of leaves from Achillea millefolium (AE) on enzyme- and non-enzyme-dependent antioxidant systems in rats. Seven days treatment with AE (1 g/kg/twice a day, p.o.) altered the reduced glutathione (GSH) levels and antioxidant enzyme activities in several organs of the animals. Amount of GSH in uterus was increased (73%) while in kidneys it was decreased (23%). Besides, NAD(P)H quinone oxidoreductase 1 (NQO1) activity was increased in forestomach (26%) and in liver (64%), while glutathione S-transferase activity was decreased in the forestomach (32%) and increased in the liver (41%), kidney (35%) and uterus (37%). In preliminary experiments targeting the interaction of AE with acetaminophen (600 mg/kg, p.o.), we observed augmentation of acetaminophen-induced increase of the plasmatic alanine aminotransaminase, aspartate aminotransaminase and lactate dehydrogenase. Overall, the results indicate a potential toxic interaction of AE compounds with xenobiotics that use the glutathione pathway.

Effect of dietary isoleucine on the immunity, antioxidant status, tight junctions and microflora in the intestine of juvenile Jian carp (Cyprinus carpio var. Jian)

This study was conducted to investigate the effects of dietary isoleucine (Ile) on the immune response, antioxidant status, tight junctions, and microbial population in the intestine of juvenile Jian carp (Cyprinus carpio var. Jian). A total of 1200 juvenile Jian carp with average initial weight 6.9 ± 0.03 g were fed semi-purified isonitrogenous diets containing 4.2 (unsupplemented control group), 7.0, 9.5, 11.9, 13.9 and 16.9 g Ile kg(-1) diet for 60 days. Results indicated that Ile supplementation decreased malondialdehyde (MDA) and protein carbonyl content, and the amounts of Escherichia coli and Aeromonas in the intestine (P < 0.05), and increased the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione reductase (GR), glutathione content and the amounts of Lactobacillus and Bacillus in the intestine (P < 0.05). Furthermore, real time polymerase chain reaction revealed that relative mRNA expression of copper/zinc superoxide dismutase (Cu-ZnSOD), manganese superoxide dismutase (MnSOD), CAT, NF-E2-related factor 2 (Nrf2), p38 mitogen-activated protein kinases (p38MAPK) in the intestine were increased with increasing of dietary Ile up to a certain point (P < 0.05). Conversely, the relative mRNA expression of occludin, claudin-3, claudin-7, TNF-α, IL-10, Kelch-like-ECH- associated protein 1 (Keap1), extracellular signal-regulated kinase 1 (ERK1) in the intestine showed a downward trend (P < 0.05). In conclusion, dietary Ile improves intestinal immune function, antioxidant capacity and microbial population, and regulates gene expression of antioxidant enzyme, tight junctions, Nrf2, Keap1, p38 and ERK1 in the intestine of Jian carp.

Effects of dietary concentrations of methionine on growth performance and oxidative status of broiler chickens with different hatching weight

1. A study was conducted to evaluate the effects of two hatching weight (HW) levels and two dietary concentrations of methionine on the growth performance and oxidative status of broilers. Male Arbor Acres chickens were divided into two groups on their HW (low and high HW, H and L). Each HW group was then distributed into two subgroups, of similar HW, receiving either low or high dietary concentrations of methionine (4.9 g methionine/kg, LM; 5.9 g methionine/kg, HM). Thus, all day-old birds were distributed into 4 treatments (H-LM, H-HM, L-LM, L-HM) × 6 replicates × 10 birds for 21 d. 2. Broilers with high HW were heavier than those with low HW during the 21 d assay, which appeared to result from increased body weight gain rather than improved feed conversion efficiency. A higher dietary concentration of methionine (5.9 g/kg) improved growth performance of broilers with low HW in terms of body weight gain and feed conversion ratio. 3. Broilers with different HW had similar antioxidant status both in serum and liver. 4. Broilers given a diet containing 5.9 g/kg methionine had enhanced serum superoxide dismutase (SOD) activity and decreased hepatic malondialdehyde (MDA) content at day 7. 5. Broilers given a diet containing 5.9 g/kg methionine had a higher hepatic reduced glutathione (GSH):glutathione disulphide (GSSG) ratio than those given a diet containing 4.9 g/kg methionine at day 21. High dietary methionine concentration reduced hepatic GSH content and glutathione peroxidase (GPX) activity of broilers with high HW at day 7 and at day 21, respectively, but increased hepatic GSH content of broilers with low HW at day 7. 6. Although broilers with different HW had similar oxidative status as indicated by several parameters in blood and liver, HW can have positive effects on the subsequent growth performance of broilers, and a higher dietary methionine concentration (5.9 g/kg) can improve growth performance and antioxidant status in broilers exhibiting low HW.

Protective effects of a novel sea buckthorn wine on oxidative stress and hypercholesterolemia

We developed a novel sea buckthorn wine containing significant in vitro free radical-scavenging activity. High-performance liquid chromatographic analysis of the sea buckthorn wine revealed that it contains high rutin, myricetin and quercetin levels compared to Cabernet Shiraz wine. In this study, we evaluated the protective effects of sea buckthorn wine against phorone-induced oxidative stress and high-cholesterol diet induced hypercholesterolemia in male LACA mice. Oral administration of sea buckthorn wine increased the redox ratio accompanied by reduction of oxidized glutathione levels leading to attenuation of phorone-induced oxidative stress. Furthermore, the sea buckthorn wine supplementation reduced hepatic lipid peroxidation and increased the superoxide dismutase activity indicating improved resistance to oxidative stress. In addition, high-cholesterol-fed mice administered with sea buckthorn wine exhibited a 197% increase in the HDL-C/LDL-C ratio compared to high-cholesterol diet treated mice. These studies provide important evidence that sea buckthorn wine exerts protective effects against oxidative stress and hypercholesterolemia.

Increased sensitivity to testicular toxicity of transplacental benzo[a]pyrene exposure in male glutamate cysteine ligase modifier subunit knockout (Gclm-/-) mice

Polycyclic aromatic hydrocarbons (PAHs), like benzo[a]pyrene (BaP), are ubiquitous environmental pollutants formed by the incomplete combustion of organic materials. The tripeptide glutathione (GSH) is a major antioxidant and is important in detoxification of PAH metabolites. Mice null for the modifier subunit of glutamate cysteine ligase (Gclm), the rate-limiting enzyme in GSH synthesis, have decreased GSH concentrations. We investigated the effects of Gclm deletion alone on male fertility and spermatogenesis and its effect on the sensitivity of male embryos to the transplacental testicular toxicity of BaP. Gclm-/- males had dramatically decreased testicular and epididymal GCL enzymatic activity and total GSH concentrations compared with Gclm+/+ littermates. Ratios of reduced to oxidized GSH were significantly increased in Gclm-/- testes. GSH reductase enzymatic activity was increased in Gclm-/- epididymides. We observed no changes in fertility, testicular weights, testicular sperm head counts, or testicular histology and subtle changes in cauda epididymal sperm counts, motility, and morphology in Gclm-/- compared with Gclm+/+ males. Prenatal exposure to BaP from gestational day 7 to 16 was dose dependently associated with significantly decreased testicular and epididymal weights, testicular and epididymal sperm counts, and with vacuolated seminiferous tubules at 10 weeks of age. Gclm-/- males exposed prenatally to BaP had greater decreases in testicular weights, testicular sperm head counts, epididymal sperm counts, and epididymal sperm motility than Gclm+/+ littermates. These results show no effects of Gclm deletion alone on male fertility and testicular spermatogenesis and subtle epididymal effects but support increased sensitivity of Gclm-/- males to the transplacental testicular toxicity of BaP.

Unveiling the roles of the glutathione redox system in vivo by analyzing genetically modified mice

Redox status affects various cellular activities, such as proliferation, differentiation, and death. Recent studies suggest pivotal roles of reactive oxygen species not only in pathogenesis under oxidative insult but also in intracellular signal transduction. Glutathione is present in several millimolar concentrations in the cytoplasm and has multiple roles in the regulation of cellular homeostasis. Two enzymes, γ-glutamylcysteine synthetase and glutathione synthetase, constitute the de novo synthesis machinery, while glutathione reductase is involved in the recycling of oxidized glutathione. Multidrug resistant proteins and some other transporters are responsible for exporting oxidized glutathione, glutathione conjugates, and S-nitrosoglutathione. In addition to antioxidation, glutathione is more positively involved in cellular activity via its sulfhydryl moiety of a molecule. Animals in which genes responsible for glutathione metabolism are genetically modified can be used as beneficial and reliable models to elucidate roles of glutathione in vivo. This review article overviews recent progress in works related to genetically modified rodents and advances in the elucidation of glutathione-mediated reactions.

Redox regulation of fertilisation and the spermatogenic process

Oxidative stress is one of the major causes of male infertility; it damages spermatogenic cells, the spermatogenic process and sperm function. Recent advances in redox biology have revealed the signalling role of reactive oxygen species (ROS) that are generated by cells. While highly reactive oxidants, such as the hydroxyl radical, exert largely deleterious effects, hydrogen peroxide can feasibly serve as a signal mediator because it is moderately reactive and membrane permeable and because it can oxidize only limited numbers of functional groups of biological molecules. The amino acid side chain most sensitive to oxidation is cysteine sulphydryl, which is commonly involved in the catalysis of some enzymes. Although the reactivity of cysteine sulphhydryl is not very high in ordinary proteins, some phosphatases possess a highly reactive sulphydryl group at their catalytic centre and are thereby oxidatively inactivated by transiently elevated hydrogen peroxide levels after extracellular stimuli and under certain environmental conditions. Peroxiredoxins, in turn, show moderate hydrogen peroxide-reducing activity, and their role in the modulation of ROS-mediated signal transduction in ordinary cells, mediated by protecting phosphatases from oxidative inactivation, has attracted much attention. Although knowledge of the signalling role of ROS in the male reproductive system is limited at present, its significance is becoming a focal issue. Here, we present a review of the emerging signalling role of hydrogen peroxide in testes.

Oxidative damage increases and antioxidant gene expression decreases with aging in the mouse ovary

Oxidative stress has been implicated in various aspects of aging, but the role of oxidative stress in ovarian aging remains unclear. Our previous studies have shown that the initiation of apoptotic cell death in ovarian follicles and granulosa cells by various stimuli is initiated by increased reactive oxygen species. Herein, we tested the hypothesis that ovarian antioxidant defenses decrease and oxidative damage increases with age in mice. Healthy, wild-type C57BL/6 female mice aged 2, 6, 9, or 12 mo from the National Institute on Aging Aged Rodent Colony were killed on the morning of metestrus. Quantitative real-time RT-PCR was used to measure ovarian mRNA levels of antioxidant genes. Immunostaining using antibodies directed against 4-hydroxynonenal (4-HNE), nitrotyrosine (NTY), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) was used to localize oxidative lipid, protein, and DNA damage, respectively, within the ovaries. TUNEL was used to localize apoptosis. Ovarian expression of glutathione peroxidase 1 (Gpx1) increased and expression of glutaredoxin 1 (Glrx1), glutathione S-transferase mu 2 (Gstm2), peroxiredoxin 3 (Prdx3), and thioredoxin 2 (Txn2) decreased in a statistically significant manner with age. Statistically significant increases in 4-HNE, NTY, and 8-OHdG immunostaining in ovarian interstitial cells and follicles were observed with increasing age. Our data suggest that the decrease in mRNA expression of mitochondrial antioxidants Prdx3 and Txn2 as well as cytosolic antioxidants Glrx1 and Gstm2 may be involved in age-related ovarian oxidative damage to lipid, protein, DNA, and other cellular components vital for maintaining ovarian function and fertility.

Knockout of the transcription factor NRF2 disrupts spermatogenesis in an age-dependent manner

Oxidative stress occurs when generation of reactive oxygen species (ROS) overwhelms antioxidant defenses. Oxidative stress has been associated with male infertility. The transcription factor nuclear factor-erythroid 2-related factor 2 (NRF2) regulates basal and inducible transcription of genes encoding enzymes important for protection against ROS. We hypothesized that deletion of the Nrf2 gene causes testicular and epididymal oxidative stress, which disrupts spermatogenesis. Our results show that male Nrf2(-/-) mice have decreased fertility compared to wild-type and heterozygous littermates, due to accumulating seminiferous tubule damage with increasing age. Testicular sperm head counts, epididymal sperm counts, and epididymal sperm motility in 2-month-old Nrf2(-/-) males did not differ from those of wild-type littermates; however, by age 6 months, Nrf2(-/-) males had 44% lower testicular sperm head counts, 65% lower epididymal sperm counts, and 66% lower epididymal sperm motility than wild-type males. Two- to 4-month-old Nrf2(-/-) males had elevated levels of testicular and epididymal lipid peroxidation and testicular germ cell apoptosis, and decreased levels of antioxidants, compared to wild-type males. These results provide evidence that oxidative stress has deleterious effects on the testis and epididymis and demonstrate a critical role for the transcription factor NRF2 in preventing oxidative disruption of spermatogenesis.

Granulosa cell subtypes vary in response to oxidized low-density lipoprotein as regards specific lipoprotein receptors and antioxidant enzyme activity

CONTEXT

The oxidized low-density lipoprotein (oxLDL) and its lectin-like oxLDL receptor-1 (LOX-1) are found in the follicular fluid and in granulosa cells. Lipoprotein receptors and antioxidant enzymes could differ in granulosa cell subtypes.

OBJECTIVE

Our aim was to reveal cell-specific responses under oxLDL treatment.

DESIGN AND SETTING

We conducted basic research at the Institute of Anatomy and the Clinic of Reproductive Medicine.

PATIENTS

Women undergoing in vitro fertilization therapy participated in the study.

MAIN OUTCOME MEASURES

Cultures of cytokeratin-positive/negative (CK(+)/CK(-)) granulosa cells and of cumulus cells were treated with 150 microg/ml oxLDL or native LDL under serum-free conditions for up to 36 h. Dead cells were determined by uptake of propidium iodide. LOX-1, toll-like receptor 4, and cluster of differentiation 36 (CD36) were examined in lysates by Western blots. The enzyme activities were determined in lysates and in supernatants.

RESULTS

Under oxLDL treatment, predominantly CK(+) cells underwent nonapoptotic cell death. Receptors showed a cell-specific pattern of up-regulation: toll-like receptor 4 in CK(+) cells, LOX-1 in CK(-) cells, and CD36 in cumulus cells. An antioxidant ranking occurred: superoxide dismutase activity in CK(+) cells, total glutathione in CK(-) cells, and catalase activity in cumulus cells. The supernatants of oxLDL-treated CK(+) cell cultures contained more catalase activity than in controls, whereas a moderate increase was noted for glutathione peroxidase (GPx) in supernatants of CK(-) and cumulus cells.

CONCLUSIONS

Catalase/GPx activity in the supernatants may be due to cell death or to secretion. Oxidative stress could be sensed by CK(+) cells and indicated by changes in catalase/GPx activity in the follicular fluid during ovarian disorders.

Nrf2-regulated glutathione recycling independent of biosynthesis is critical for cell survival during oxidative stress

Nuclear factor-erythroid 2 p45-related factor 2 (Nrf2) is the primary transcription factor protecting cells from oxidative stress by regulating cytoprotective genes, including the antioxidant glutathione (GSH) pathway. GSH maintains cellular redox status and affects redox signaling, cell proliferation, and death. GSH homeostasis is regulated by de novo synthesis as well as GSH redox state; previous studies have demonstrated that Nrf2 regulates GSH homeostasis by affecting de novo synthesis. We report that Nrf2 modulates the GSH redox state by regulating glutathione reductase (GSR). In response to oxidants, lungs and embryonic fibroblasts (MEFs) from Nrf2-deficient (Nrf2(-/-)) mice showed lower levels of GSR mRNA, protein, and enzyme activity relative to wild type (Nrf2(+/+)). Nrf2(-/-) MEFs exhibited greater accumulation of glutathione disulfide and cytotoxicity compared to Nrf2(+/+) MEFs in response to t-butylhydroquinone, which was rescued by restoring GSR. Microinjection of glutathione disulfide induced greater apoptosis in Nrf2(-/-) MEFs compared to Nrf2(+/+) MEFs. In silico promoter analysis of the GSR gene revealed three putative antioxidant-response elements (ARE1, -44; ARE2, -813; ARE3, -1041). Reporter analysis, site-directed mutagenesis, and chromatin immunoprecipitation assays demonstrated binding of Nrf2 to two AREs distal to the transcription start site. Overall, Nrf2 is critical for maintaining the GSH redox state via transcriptional regulation of GSR and protecting cells against oxidative stress.

Regulation of key antioxidant enzymatic systems in the sheep endometrium by ovarian steroids

Reactive oxygen species (ROS) and their control by antioxidant enzymes are involved in the physiology of the female reproductive system. Thus, it is important to understand the regulation of key antioxidant enzymatic pathways. The roles of estrogen and progesterone in regulating the physiological functions of the endometrium have become central dogma. We examined the effects of ovarian steroids on superoxide dismutases (SOD1 and SOD2), catalase (CAT), glutathione peroxidase (GPX), and glutathione reductase (GSR) activities in the aglandular caruncular and glandular inter-caruncular endometrial tissues of ovariectomized (OVX) ewes and in OVX ewes treated with estradiol (E2), progesterone (P4), or both hormones according to schedules designed to produce physiological changes of these hormones during the estrous cycle. The activities SOD2, CAT, GPX and GSR in both endometrial tissues were unaffected by P4 treatment. The activity of SOD1 in the aglandular tissue was unaffected by P4 treatment, however this treatment decreased SOD1 activity in the glandular tissue (P < 0.01). Treatment with E2, either alone or in combination with P4, decreased SOD1 (P < 0.01), CAT (P < 0.01) and GPX (P < 0.05) activities in both endometrial tissues. The activity of GSR decreased only in the glandular tissue (P < 0.05) after E2 treatment, either alone or in combination with P4. No change in SOD2 activity was detected in both endometrial tissues after administration of E2, P4 or both hormones. This study provides the first firm evidence for the role of ovarian steroid hormones in the regulation of the activities of key antioxidant enzyme in the endometrium of female mammals.

Antioxidant activity of Bol d'Air Jacquier breathing sessions in Wistar rats--first studies

OBJECTIVES

The Bol d'Air Jacquier is used to create a molecule able to deliver oxygen at the cellular level to manage hypoxia due to environmental pollution, ageing, or inflammatory disease. This study was designed to determine, firstly, whether the device generated oxidative stress and, secondly, whether it might induce an antioxidant effect.

MATERIAL AND METHODS

Over a period of 62 weeks, 10 male Wistar rats were randomized into two groups: the Bol d'Air group (BA) regularly breathed peroxidizing terpens delivered by the device and the control group breathed water vapour during 9-min sessions, at the frequency of 1-12 per month. Several antioxidant compounds and KRL levels were determined in the blood and major organs.

RESULTS

The results showed that the two groups did not differ with respect to the organ concentrations of Cu, Zn SOD, GPx, GSH, GSSG and TBARS. The device might have a weak slimming effect over time. The BA group presented a significantly higher GR level in plasma throughout the experiment, and in the muscle at the end of the study. In the BA group, the plasma Cu, Zn SOD level was related to the number of breathing sessions per week before blood collection. The BA group also had a higher KRLantioxidant status at two different time-points: at the onset of the study, in the blood of young rats; and after three breathing sessions per week, in the blood and RBCs of old rats.

CONCLUSIONS

The device did not generate oxidative stress and seemed to produce global antioxidant effect depending on the number of sessions per week, especially in old rats.

Comparison between the effects of normoxia and hypoxia on antioxidant enzymes and glutathione redox state in ex vivo culture of CD34(+) cells

Hypoxia maintained biological characteristics of CD34(+) cells through keeping lower intracellular reactive oxygen specials (ROS) levels. The effects of normoxia and hypoxia on antioxidant enzymes and glutathione redox state were compared in this study. Hypoxia decreased the mRNA expression of both catalase (CAT) and glutathione peroxidase (GPX), but not affected mRNAs expression of superoxide dismutase (SOD). While the cellular GPX activities under hypoxia were apparently less than those under normoxia, neither SOD activities nor CAT activities were affected by hypoxia. The analysis of glutathione redox status and ROS products showed the lower oxidized glutathione (GSSG) levels, the higher reduced glutathione (GSH) levels, the higher GSH/GSSG ratios, and the less O(2)- and H(2)O(2) generation under hypoxia (versus normoxia). Meanwhile more primary CD34(+)CD38(-) cells were obtained when cultivation was performed under hypoxia or with N-acetyl cysteine (the precursor of GSH) under normoxia. These results demonstrated the different responses of anti-oxidative mechanism between normoxia and hypoxia. Additionally, the present study suggested that the GSH-GPX antioxidant system played an important role in HSPCs preservation by reducing peroxidation.

Antioxidant status of the lower oviduct in the chicken varies with age and dietary vitamin E supplementation

Protection of sperm membranes against lipid peroxidation is a pre-requisite to prolonged sperm storage, both in vivo and in vitro. As females from avian species can store spermatozoa in the utero-vaginal junction (UVJ) for prolonged periods, we investigated the mechanisms involved in antioxidative protection of the plasma membrane of chicken sperm in this region. Comparisons of concentrations in nonenzymatic (alpha-tocopherol, ascorbic acid, and GSH) and enzymatic (GSH-Px, SOD) antioxidants among the vagina, UVJ and uterus of sexually mature chicken hens revealed tissue-specific profiles, with higher ascorbic acid content and increased GSH-Px and SOD activity in the UVJ compared to other regions of the lower oviduct (vagina, uterus). Deterioration of the antioxidant profile in the UVJ was observed in aging hens, but it was partially compensated by dietary supplementation with vitamin E (130 ppm). It is concluded that the chicken UVJ provides a complex defense barrier against lipid peroxidation of the sperm membrane during in vivo storage, which can be partially improved by dietary supplementation with vitamin E. The protective effects of this barrier decline over time during the reproductive season.

Fundamental roles of reactive oxygen species and protective mechanisms in the female reproductive system

Controlled oxidation, such as disulfide bond formation in sperm nuclei and during ovulation, plays a fundamental role in mammalian reproduction. Excess oxidation, however, causes oxidative stress, resulting in the dysfunction of the reproductive process. Antioxidation reactions that reduce the levels of reactive oxygen species are of prime importance in reproductive systems in maintaining the quality of gametes and support reproduction. While anti-oxidative enzymes, such as superoxide dismutase and peroxidase, play a central role in eliminating oxidative stress, reduction-oxidation (redox) systems, comprised of mainly glutathione and thioredoxin, function to reduce the levels of oxidized molecules. Aldo-keto reductase, using NADPH as an electron donor, detoxifies carbonyl compounds resulting from the oxidation of lipids and proteins. Thus, many antioxidative and redox enzyme genes are expressed and aggressively protect gametes and embryos in reproductive systems.

The effects of BIS-GMA and TEG-DMA on female mouse fertility

OBJECTIVES

The current study evaluated the effect of bisphenol A glycerolate dimethacrylate (BIS-GMA) and triethyleneglycol dimethacrylate (TEG-DMA) on female mouse fertility.

METHODS

Adult female mice were exposed to BIS-GMA or TEG-DMA (0, 25 and 100 microg/kg) intragastrically daily for 28 d and then mated with sexually mature untreated male mice and after mating their fertility was assessed.

RESULTS

In females exposed to BIS-GMA at both doses significant increases in the total number of resorptions out of the total number of implantations were observed, with a significant increase in the number of animals with resorptions at the higher dose. Significant reductions in body weights and significant increases in ovary weights were also observed. Exposure to TEG-DMA at a dose of 100 microg/kg resulted in significant reductions in pregnancy rates and a significant increase in the total number of embryonal resorptions. Significant reductions in body and uterine weights were also observed in females exposed to TEG-DMA.

SIGNIFICANCE

The results suggest that both BIS-GMA and TEG-DMA have reproductive toxic effects in female mice.

Glutathione reductase is expressed at high levels in pancreatic islet cells

Reactive oxygen species are, at least partly, involved in the diabetogenic agent-induced dysfunction of pancreatic beta-cells because the expression of antioxidative and redox proteins is low. We examined the levels of antioxidant/redox proteins, peroxiredoxins-1, -4, and -6 and glutathione reductase (GR), by immunohistochemistry and found that the expression of GR was very high in pancreatic islet cells compared to exocrine cells. When diabetes was induced by an intravenous injection of streptozotocin, the pre-administration of 1,3-bis[2-chloroethyl]-1-nitrosourea, an irreversible inhibitor of GR, made islet cells more vulnerable to streptozotocin. These data point to a pivotal role of the glutathione redox system in pancreatic islet cells against diabetogenic stress.

Role of glutathione in reproductive tract secretions on mouse preimplantation embryo development

We investigated the hypothesis that glutathione (GSH) in reproductive tract secretions (RTS) protects the preimplantation embryo from endogenous reactive oxygen species and is important for normal development during the embryo's sensitive period when it is incapable of synthesizing GSH de novo. Mice were administered buthionine sulfoximine (BSO) to inhibit GSH synthesis and decrease GSH concentration in RTS. Embryos were then allowed to develop either in vivo or in vitro in the presence of RTS and the GSH concentration of the embryos was quantified by HPLC and embryonic development was recorded. GSH concentration in RTS did not differ over the phases of the estrous cycle, but there were significant decreases in GSH concentration on Day 2 of gestation and due to BSO treatment. Embryos allowed to develop in vivo and in vitro in RTS with decreased GSH concentration did not exhibit decreased development or GSH concentration. Oocytes exposed to BSO during maturation in vivo experienced a significant decrease in GSH concentration and an increase in percent of degenerate embryos when compared with control. These data suggest that most of the GSH in RTS does not play a critical role in normal preimplantation embryo development but that GSH stored in the oocyte during maturation has an important role in subsequent embryo development. Our studies do not exclude the possibility that GSH in RTS plays an important role in protection of the preimplantation embryo during exposure to some toxicants.

Detection of S-glutathionylated proteins by glutathione S-transferase overlay

Oxidative and nitrosative stress lead to the S-glutathionylation of proteins and subsequent functional impairment. Glutathione S-transferase (GST) from Schistosoma japonicum was found to bind to the glutathione moiety of S-glutathionylated proteins, thus establishing a convenient method for detecting S-glutathionylated proteins by biotinylated GST. Applications of this method to proteins that were prepared from cultured cells and blotted onto a membrane exhibited numerous positive bands, which were abolished by treatment with dithiothreitol. Treatment of a cellular extract with nitrosoglutathione led to enhanced staining of the bands in a dose-dependent manner. The method was also applicable for the histochemical detection of S-glutathionylated proteins in situ. The positive staining by biotin-GST became faint in the presence of S-glutathionylated ovalbumin, suggesting that the reaction is specific to S-glutathionylated proteins. Collectively, these data indicate that the method established here is simple and useful for detecting S-glutathionylated proteins on blotted membrane and in situ.

Regulation of sperm function by reactive oxygen species

Sperm capacitation can be increased by the addition of reactive oxygen species (ROS) and decreased by antioxidants. Broadly consistent results have been achieved with a wide variety of methods and across different species. Exposure to ROS increases protein tyrosine phosphorylation consequent on an increase in cAMP and activation of tyrosine kinase and inhibition of tyrosine phosphatase. The measurement of ROS production by sperm is complicated by contamination of suspensions by leukocytes, laying many studies open to doubt. In human sperm the observation that extracellular NADPH could support superoxide production detected with the chemiluminescent probe lucigenin and had physiological effects similar to hydrogen peroxide led to the suggestion that they contained NADPH oxidase activity to generate ROS to support capacitation. However, the realization that lucigenin can signal superoxide artefactually, combined with failure to detect superoxide production using spin trapping techniques or to detect NADPH oxidase components in mature sperm, and confirmation of old reports that NADPH solution contains substantial amounts of hydrogen peroxide due to autoxidation, have undermined this hypothesis. Although the presence of significant NADPH oxidase activity in mature human sperm now seems less likely, other observations continue to suggest that they can make ROS in some way. There is stronger evidence that animal sperm can make ROS although these may be mainly of mitochondrial origin.

Transcriptome of mouse uterus by serial analysis of gene expression (SAGE): Comparison with skeletal muscle

The aim of this study was to identify the transcriptome of the normal mouse uterus by Serial Analysis of Gene Expression method. mRNA was extracted from the uterus and also from the gastrocnemius muscle of mice. Short sequences (tags), each one usually corresponding to a distinct transcript, were isolated and concatemerized into long DNA molecules which were cloned and sequenced. We detected 44,484 tags for the uterus and 42,518 tags for the muscle, representing 14,543 and 14,958 potential transcript species, respectively. Seventy-five and sixty-nine genes were expressed at more than 0.1%, thus corresponding to 37 and 34% of the mRNA population detected in the respective tissues. In both cases, the most highly expressed genes are especially involved in muscle contraction, energy metabolism, and protein synthesis. Compared to skeletal muscle, some differentially expressed genes in the uterus are likely to correspond to its specific reproductive functions. The majority of these genes remain to be characterized. More than 70% of the different tags detected in the uterus did not match any sequence in the public databases and can represent novel or poorly identified genes. This study is the first quantitative description of the transcriptome of the uterus.

Influence of selenium sources on age-related and mild heat stress-related changes of blood and liver glutathione redox cycle in broiler chickens (Gallus domesticus)

Selenium is an essential trace element that up-regulates a major component of the antioxidant defense mechanism by controlling the body's glutathione (GSH) pool and its major Se-containing antioxidant enzyme, glutathione peroxidase (GPX). Evidence has emerged suggesting that organic selenium, natural seleno-amino acids found in plants, grains and selenized yeast, maintains the antioxidant defense system more efficiently than inorganic selenium. Inorganic selenium is a pro-oxidant, whereas organic selenium possesses antioxidant properties itself. As a pro-oxidant, inorganic selenium is not suitable for animals or humans. Therefore, we examined the GSH-GPX system in broiler chickens and determined that organic selenium was indeed more beneficial than inorganic selenium. Chickens fed the organic selenium as Sel-Plex, a selenized yeast, had elevated GPX activity in both blood and liver in a thermoneutral environment and after heat distress. More importantly, the ability to reduce the oxidized glutathione (GSSG to 2 GSH) was enhanced and facilitated by maintenance of glutathione reductase activity. Organic selenium-fed chickens were less affected by mild heat distress than inorganic selenium-fed chickens, and this assessment was based upon less induction of heat shock protein 70 (hsp70) in organic selenium-fed chickens. Our results clearly show that heat distress, a potent inducer of oxidative stress and hsp70, can be partially ameliorated by feeding organic selenium. We attribute this observation to an enhanced GSH-GPX antioxidant system in organic selenium-fed chickens.

Male genital tract antioxidant enzymes: their source, function in the female, and ability to preserve sperm DNA integrity in the golden hamster

Recently, we reported that male accessory sex gland (ASG) secretions protect sperm genomic integrity by demonstrating that DNA damage was more extensive in sperm not exposed to the secretions. The present study was conducted to find out if ASGs secrete the main antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GPx or GSH-Px), and catalase (CAT) and if the most abundant one, SOD, can protect those sperm that were not exposed to ASG secretions against NADPH-induced oxidative stress. Four experimental groups of male golden hamsters were used: intact animals with proven fertility, animals with all major ASGs removed (TX), animals that were bilaterally vasectomized, and sham-operated controls. SOD, CAT, and GPx activities were measured in secretions from all 5 ASGs and sperm-free uterine flushing from virgin females and those mated with the experimental males. The alkaline comet assay was used to analyze DNA integrity of the TX group sperm after incubation in a medium containing 50 U/mL of SOD along with 0 to 20 mmol/L NADPH. The main antioxidant enzyme in ASGs was SOD from coagulating glands (P <.05) and GPx together with CAT from ampullary glands (P <.05). Uterine flushing of ejaculates that contained ASG secretions had more SOD and CAT activities than those with epididymal secretions alone (P <.05 and P <.001, respectively), whereas activity of GPx was the same (P >.05). Addition of SOD in vitro dose dependently decreased the incidence of single-strand DNA damage in sperm not exposed to ASG secretions incubated in the presence of 0 to 20 mmol/L NADPH (P <.001). These results indicated that, in terms of abundance, SOD was the main antioxidant enzyme secreted by male ASGs, whereas CAT was the second one. The GPx activity came from both epididymis and ASGs. We conclude that ASG secretions play a significant role in protecting sperm against oxidative stress.

Localization of glutamate cysteine ligase subunit mRNA within the rat ovary and relationship to follicular apoptosis

Ovarian levels of the antioxidant tripeptide glutathione (GSH) increase following gonadotropin administration, suggesting that GSH synthesis in the ovary may be associated with follicular growth. In situ hybridization with (35)S-labeled riboprobes was used to localize ovarian mRNA expression of the catalytic and modulatory subunits of glutamate cysteine ligase (Gclc and Gclm), the rate-limiting enzyme in GSH synthesis, during each stage of the rat estrous cycle. Gclm was highly expressed in the granulosa cells and oocytes of healthy, growing follicles, not in atretic follicles. Gclc was also highly expressed in follicles; however, unlike Gclm, Gclc was also expressed in corpora lutea and interstitial cells. In a subsequent experiment, the hypothesis that GSH synthesis occurs in healthy, but not in apoptotic, follicles was tested. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) was used to detect apoptotic cells in the ovaries, and in situ hybridization for Gclm and Gclc was performed in adjacent sections of the same ovaries. TUNEL staining was found to be significantly associated with absence of Gclm hybridization in granulosa cells and oocytes and with lack of strong Gclc hybridization in granulosa cells. These results suggest that follicular apoptosis may be associated with down-regulation of Gclm and Gclc transcription in granulosa cells and oocytes.

Colocalization of polyol-metabolizing enzymes and immunological detection of fructated proteins in the female reproductive system of the rat

The expression of aldose reductase (AR) and sorbitol dehydrogenase (SDH), which, in concert, catalyze the conversion of glucose to fructose via sorbitol, in the rat ovary, oviduct, and uterus, was investigated by immunohistochemical and biochemical analyses. The activities and protein levels of AR and SDH were higher in the ovary than in the oviduct and uterus. A strong immunoreactivity to the anti-AR antibody was observed in granulosa cells and epithelia of the oviduct, endometrium, and endometrial glands, and virtually the same tissues were strongly stained with the anti-SDH antibody. The application of an anti-fructated lysine antibody, which detects an adduct of fructose with the epsilon-amino group of lysine in proteins, in this study detected marked staining mainly in the egg and luminal surface of the oviductal epithelia. Collectively, these data indicate that fructose is produced by coordinately expressed AR and SDH in the egg and epithelia of the oviduct and suggest that the resulting sorbitol and fructose can be used as energy sources for spermatozoa motility during the fertilization process. The abundance of AR compared with SDH suggests that it also plays an additional role in the reproductive system, which might include a source of reducing power and protection against toxic carbonyl compounds.

The expression of glutathione reductase in the male reproductive system of rats supports the enzymatic basis of glutathione function in spermatogenesis

Glutathione reductase (GR) recycles oxidized glutathione (GSSG) by converting it to the reduced form (GSH) using an NADPH as the electron source. The function of GR in the male genital tract of the rat was examined by measuring its enzymatic activity and examining the gene expression and localization of the protein. Levels of GR activity, the protein, and the corresponding mRNA were the highest in epididymis among testes, vas deferens, seminal vesicle, and prostate gland. The localization of GR, as evidenced by immunohistochemical techniques, reveals that it exists at high levels in the epithelia of the genital tract. In testis, GR is mainly localized in Sertoli cells. The enzymatic activity and protein expression of GR in primary cultured testicular cells confirmed its predominant expression in Sertoli cells. Intracellular GSH levels, expressed as mol per mg protein, was higher in spermatogenic cells than in Sertoli cells. As a result of these findings, the effects of buthionine sulfoximine (BSO), an inhibitor for GSH synthesis, and 1,3-bis(2-chlorethyl)-1-nitrosourea (BCNU), an inhibitor for GR, on cultured testicular cells were examined. Sertoli cells were prone to die as the result of BCNU, but not BSO treatment, although intracellular levels of GSH declined more severely with BSO treatment. Spermatogenic cells were less sensitive to these agents than Sertoli cells, which indicates that the contribution of these enzymes is less significant in spermatogenic cells. The results herein suggest that the GR system in Sertoli cells is involved in the supplementation of GSH to spermatogenic cells in which high levels of cysteine are required for protamine synthesis. In turn, the genital tract, the epithelia of which are rich in GR, functions in an antioxidative manner to protect sulfhydryl groups and unsaturated fatty acids in spermatozoa from oxidation during the maturation process and storage.