Lipid peroxidation and activity of antioxidant enzymes in diabetic rats

We hypothesized that oxygen free radicals (OFRs) may be involved in pathogenesis of diabetic complications. We therefore investigated the levels of lipid peroxidation by measuring thiobarbituric acid reactive substances (TBARS) and activity of antioxidant enzymes [superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT)] in tissues and blood of streptozotocin (STZ)-induced diabetic rats. The animals were divided into two groups: control and diabetic. After 10 weeks (wks) of diabetes the animals were sacrificed and liver, heart, pancreas, kidney and blood were collected for measurement of various biochemical parameters. Diabetes was associated with a significant increase in TBARS in pancreas, heart and blood. The activity of CAT increased in liver, heart and blood but decreased in kidney. GSH-Px activity increased in pancreas and kidney while SOD activity increased in liver, heart and pancreas. Our findings suggest that oxidative stress occurs in diabetic state and that oxidative damage to tissues may be a contributory factor in complications associated with diabetes.     

Oxidative stress and antioxidant capacity of a terrestrially hibernating hatchling turtle

Hatchlings of the painted turtle, Chrysemys picta, hibernate terrestrially and can survive subfreezing temperatures by supercooling or by tolerating the freezing of their tissues. Whether supercooled or frozen, an ischemic hypoxia develops because tissue perfusion is limited by low temperature and/or freezing. Oxidative stress can occur if hatchlings lack sufficient antioxidant defenses to minimize or prevent damage by reactive oxygen species. We examined the antioxidant capacity and indices of oxidative damage in hatchling C. picta following survivable, 48 h bouts of supercooling (−6°C), freezing (−2.5°C), or hypoxia (4°C). Samples of plasma, brain, and liver were collected after a 24 h period of recovery (4°C) and assayed for Trolox-equivalent antioxidant capacity (TEAC), thiobarbituric acid reactive substances (TBARS), and carbonyl proteins. Antioxidant capacity did not vary among treatments in any of the tissues studied. We found a significant increase in TBARS in plasma, but not in the brain or liver, of frozen/thawed hatchlings as compared to untreated controls. No changes were found in the concentration of TBARS or carbonyl proteins in supercooled or hypoxia-exposed hatchlings. Our results suggest that hatchling C. picta have a well-developed antioxidant defense system that minimizes oxidative damage during hibernation.     

Diminution of tissue lipid peroxidation in rats is related to the in vitro antioxidant capacity of wine

Wine polyphenols could reinforce the endogenous antioxidant system, thereby diminishing oxidative damage. Studies in chronic models to understand the relationship between the bioavailability of polyphenols and their biological effects are still lacking. The aim of the present study was to prove the hypothesis that the antioxidant capacity of wines in vitro is positively correlated with the antioxidant capacity of plasma and negatively correlated with tissue lipid peroxidation, after chronic wine consumption. Adult rats received: water (control group), wine having variable phenolic content, ethanol (12.5% v/v) or alcohol-free red wine, for 4 weeks. The antioxidant capacity of wines in vitro and that of plasma induced in vivo were assessed through the reduction of ferric iron (FRAP, ferric reducing ability of plasma). Lipid peroxidation (production of thiobarbituric acid reactive substances, TBARS), and the activity of the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), were determined in kidney, liver and lung. The phenolic content of wines was positively correlated with their FRAP values in vitro (r=0.407, p <0.002). Also, the relationship between wine FRAP in vitro to its respective plasma value in vivo showed a positive correlation (r=0.433, p <0.005). Phenolic concentration of wine did not influence the activity of CAT, SOD and GSH-Px of the three organs studied, but it was negatively correlated with their production of TBARS (r=-0.852, -0.891 and -0.790 for kidney, liver and lung, respectively, p <0.001). The present data provide evidence that the antioxidant capacity of wine in vitro implicates a homologous effect in vivo, thus helping to modulate tissue lipid peroxidation.     

Anti-hyperglycemic and anti-oxidative effect of aqueous extract of Momordica charantia pulp and Trigonella foenum graecum seed in alloxan-induced diabetic rats

Diabetes is an oxidative stress disorder and oxidative damage to tissues such as heart, kidney, liver and other organs may be a contributory factor to several diabetic complications. Momordica charantia (family: Cucurbitaceae) and Trigonella foenum graecum (family: Fabaceae) are used traditionally in Indian folk medicine to manage diabetes mellitus. In the present study, the anti-hyperglycemic and anti-oxidative potential of aqueous extracts of M. charantia pulp and seed powder of T. foenum graecum were assessed in alloxan (150 mg/kg body weight) induced diabetic rats. Alloxan treatment to the rats could induce diabetes as the fasting blood glucose (FBG) levels were > 280 mg/dl. Treatment of diabetic rats for 30 days with M. charantia and T. foenum graecum could significantly (p < 0.001) improve the FBG levels to near normal glucose levels. Antioxidant activities (superoxide dismutase, catalase, reduced glutathione content and glutathione-s-transferase) and lipid peroxidation levels were measured in heart, kidney and liver tissues of normal, diabetic and experimental animals (diabetics + treatment). TBARS levels were significantly (p < 0.001) higher and anti-oxidative activities were found low in diabetic group, as compared to the control group. Significant (p < 0.001) improvement in both the TBARS levels and antioxidant activities were observed when M. charantia and T. foenum graecum were given to diabetic rats. Our results clearly demonstrate that M. charantia and T. foenum graecum are not only useful in controlling the blood glucose levels, but also have antioxidant potential to protect vital organs such as heart and kidney against damage caused due to diabetes induced oxidative stress.     

Effect of gender differences and voluntary exercise on antioxidant capacity in rats

The effects of gender difference and voluntary exercise on antioxidant capacity in rats were evaluated. The subjects were divided into two groups, physically active and sedentary. In the sedentary group, the level of hydroxyl radical in the liver was higher (P<0.001) in male rats than in female rats, however, in the physically active group, the level in male rats was lower (P<0.05) than in female rats. The levels of reduced glutathione (GSH) in physically active males and females were higher compared to those in the sedentary group. The physically active group also showed an increase in antioxidant enzymes, such as glutathione peroxidase (GPx), glutathione reductase (GR) and superoxide dismutase activities. The level of liver GSH was higher in physically active females than in physically active males. For both groups, GPx and GR activities in females were significantly higher than in males. These results indicate that female rats have an intrinsically higher antioxidant capacity, which resulted in increased levels of GSH via the glutathione redox cycle and gamma-glutamyl cycle enzymes. The adaptation to altered antioxidant capacity, induced by physical activity, appeared to be affected by gender differences.     

Immobilization stress in rat tissues: alterations in protein oxidation, lipid peroxidation and antioxidant defense system

We determined the effects of immobilization stress on antioxidant status, protein oxidation and lipid peroxidation in brain, liver, kidney, heart and stomach of rats. Sixteen male Wistar rats (3 months old) were divided into controls (C) and immobilization stress group (IS). IS rats were immobilized for 180 min/day for 15 days. Plasma corticosterone levels were increased in IS group. Copper,zinc-superoxide dismutase activities were increased in brain, liver and kidney, but decreased in the heart and stomach after immobilization. Catalase activities were increased in brain, kidney and heart, and decreased in liver and stomach. Selenium-dependent glutathione peroxidase activities were decreased in brain and kidney, but increased in heart and stomach. Reduced glutathione levels were decreased, while protein carbonyl, conjugated dienes and thiobarbituric acid-reactive substances levels were increased in all tissues. Our results showed that the response of antioxidant defense system to stress differs for each tissue, and protein oxidation and lipid peroxidation is induced by immobilization stress in peripheral tissues.     

Alterations in antioxidant enzymes and oxidative damage in experimental diabetic rat tissues: Effect of vanadate and fenugreek (Trigonella foenum graecum)

With the premise that oxygen free radicals may be responsible for the severity and complications of diabetes, the level of antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) as well as the oxidative damage were examined in the tissues of control, diabetic and treated rats. After three weeks of diabetes, the activity of CAT was significantly increased in heart in diabetes (about 6-fold) but decreased in liver. The SOD activity decreased significantly in liver but increased in brain. The activity of GPx decreased significantly in liver and increased in kidney. A significant increase was observed in oxidative damage in heart and kidney and a small increase in brain with decrease in liver and muscle. Vanadate and fenugreek (Trigonella foenum graecum) administration to diabetic animals showed a reversal of the disturbed antioxidant levels and peroxidative damage. Results suggest that oxidative stress play a key role in the complications of diabetes. Vanadate and fenugreek seeds showed an encouraging antioxidant property and can be valuable candidates in the treatment of the reversal of the complications of diabetes.     

Effects of angiotensin II type 1 receptor blockade on the oxidative stress in spontaneously hypertensive rat tissues

The aim of this work was to investigate the production of oxidative damage in homogenized kidney, liver and brain of spontaneously hypertensive rats (SHR), as well as the involvement of angiotensin (Ang) II in this process. Groups of 12-week-old SHR and Wistar Kyoto rats (WKY) were given 10 mg/kg/day losartan in the drinking water during 14 days. Other groups of WKY and SHR without treatment were used as controls. The production of thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH) and the activity of the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (Gpx) were determined. No significant difference in TBARS was observed between untreated SHR or WKY rats; GSH content was lower in the liver but higher in the brain of SHR compared to WKY rats. In tissues from the SHR group, SOD and Gpx activities were reduced, whereas CAT activity was slightly increased in kidney. TBARS levels did not change in WKY rats after losartan administration, but were reduced in SHR liver and brain. Losartan treatment decreased GSH content in WKY kidney, but increased GSH in SHR liver. The activity of the antioxidant enzymes was not modified by losartan in WKY rats; however, their activities increased in tissues from treated SHR. The lower activity of antioxidant enzymes in tissues from hypertensive rats compared to those detected in normotensive controls, indicates oxidative stress production. Ang II seems to play no role in this process in normotensive animals, although AT1 receptor blockade in SHR enhances the enzymatic activity indicating that Ang II is implicated in oxidative stress generation in the hypertensive animals.     

Increased hepatic lipid soluble antioxidant capacity as compared to other organs of streptozotocin-induced diabetic rats: a cyclic voltammetry study

It has been suggested that oxidative stress plays an important role in the chronic complications of diabetes. The experimental findings regarding the changes in tissue antioxidant enzymes and lipid peroxidation of diabetic tissues have been inconsistent. Previous studies in our laboratory demonstrated that the reducing power of a specific tissue correlates with its low molecular weight antioxidant (LMWA) capacity. In the present study, the overall LMWA capacity (reducing equivalents) of plasma and tissues of streptozotocin (STZ)-induced diabetic rats (1-4 weeks) and insulin treated diabetic rats were measured by cyclic voltammetry. Levels of water and lipid soluble LMWA capacity progressively decreased in the diabetic plasma, kidney, heart and brain, while the diabetic liver, at 2, 3 and 4 weeks after STZ injection, showed a significant increase in the overall lipid soluble LMWA capacity (p < 0.001). Subsequently, analysis of specific components by high pressure liquid chromatography (electrochemical detection) showed decreased levels of ascorbic acid in plasma, kidney, heart and brain of diabetic animals. The alpha-tocopherol level dropped in all tissues, except for the liver in which there was a significant increase (p < 0.01 and p < 0.001 at 2-4 weeks). Lipid peroxidation was assessed by conjugated diene levels, which increased significantly in all diabetic tissues except the liver. Insulin treatment that was started after 3 weeks of diabetes and continued for 3 weeks showed no change in the conjugated dienes and in the overall LMWA capacity in all organs. Our results suggest a unique behavior of the liver in the STZ-induced diabetic rats to the stress and indicate its higher capacity to cope with oxidative stress as compared to other organs.     

自发性高血压大鼠多组织炎症状态

高血压是一种慢性血管性疾病,易累及肾、肝、心、脑等组织,引起脑卒中和心、肾损害等并发症.本研究对高血压时肾、肝、心、脑等组织的炎症状态进行了观察.实验采用自发性高血压大鼠(spontaneously hypertensive rat,SHR)和正常血压的Wistar-Kyoto(WKY)大鼠,用RT-PCR和Western blot法观察肾、肝、心、脑等组织炎症相关因子IL-1p、TNFα、ICAM-1、iNOS、C/EBPδ和PPARγ的基因表达;紫外分光光度法观察蛋白质羰基化水平和FRAP法检测组织总抗氧化能力.结果显示(1)SHR组织炎症相关因子表达较对照WKY增强,除IL-1βmRNA在肝和脑的增加不明显外,其余均有显著性差异(P＜0.05);(2)SHR和WKY大鼠肾、心、脑蛋白质羰基化水平(nmol/mg蛋白)分别为8.93±1.08和2.27±0.43、2.23±0.23和0.17±0.02、13.42±1.10和5.72±1.01,SHR明显增加(P＜0.05);而肝脏蛋白质羰基化水平无明显变化;(3)SHR肾、肝、心、脑总抗氧化能力水平显著低于WKY大鼠(P＜0.05).以上结果表明,SHR多个组织(肾、肝、心和脑)均存在炎症因子被诱导和氧化应激反应等明显的炎症状态,提示炎症可能在高血压及其并发症的病理改变中起重要作用.     

Oxidative damage and plasma antioxidant capacity in relation to body size,age, male sexual traits and female reproductive performance in the collared flycatcher (<Emphasis Type="Italic">Ficedula albicollis</Emphasis>)

The study of oxidative stress is a potential tool for studying the functional interactions among life history traits, sexual traits and physiological status in animals. In this study, we investigated relationships between measures of plasma oxidative status and male sexual traits, female reproductive investment and three other life history traits, in a wild population of collared flycatchers (Ficedula albicollis). Flycatcher males with a larger white forehead patch had higher level of plasma antioxidant capacity. For females, clutch size was not associated with plasma oxidative status, but egg size was positively correlated with antioxidant capacity. The relationship between age and levels of plasma oxidative damage remains controversial in this species: young female flycatchers showed higher levels of hydroperoxides compared to antioxidants, whereas age did not predict oxidative status of males. Males had higher levels of oxidative damage than females, although the concentration of antioxidant compounds was similar between the sexes. Females that mated with more ornamented males had higher plasma antioxidant capacity. Our results suggest that, for males and females, greater investment in sexual signal and reproduction, respectively, does not reduce the capacity for self-maintenance or avoidance of oxidative stress. Finally, our data support indirectly the occurrence of assortative mating in our species, since females with higher plasma antioxidant capacity mated with more ornamented males.     

Sex-dependent differences in aged rat brain mitochondrial function and oxidative stress

Females show lower incidences of several neurodegenerative diseases related to oxidative stress and mitochondrial dysfunction than males. In addition, female rats show more differentiated mitochondria than males in several tissues. The aim of this work was to investigate the existence of sex-dependent differences in brain mitochondrial bioenergetics and oxidative balance in aged rats. Results showed that aged female rat brain had a lower mitochondria content than aged male brain but with a greater differentiation degree given the higher mitochondrial protein content and mitochondrial complex activities in females. Female rat brain also showed a better oxidative balance than that of males, reflected by the fact that higher mitochondrial respiratory chain function is accompanied by a similar ROS production and greater antioxidant enzyme activities, which could be responsible for the lesser oxidative damage observed in proteins and lipids in this sex. Interestingly, levels of UCP4 and UCP5--proteins related to a decrease in ROS production--were also higher in females. In conclusion, aged female rat brain had more differentiated mitochondria than male brain and showed a better control of oxidative stress balance, which could be due, in part, to the neuroprotective effect of UCPs.     

Increased hepatic lipid soluble antioxidant capacity as compared to other organs of streptozotocin-induced diabetic rats: A cyclic voltammetry study

It has been suggested that oxidative stress plays an important role in the chronic complications of diabetes. The experimental findings regarding the changes in tissue antioxidant enzymes and lipid peroxidation of diabetic tissues have been inconsistent. Previous studies in our laboratory demonstrated that the reducing power of a specific tissue correlates with its low molecular weight antioxidant (LMWA) capacity. In the present study, the overall LMWA capacity (reducing equivalents) of plasma and tissues of streptozotocin (STZ)-induced diabetic rats (1–4 weeks) and insulin treated diabetic rats were measured by cyclic voltammetry. Levels of water and lipid soluble LMWA capacity progressively decreased in the diabetic plasma, kidney, heart and brain, while the diabetic liver, at 2, 3 and 4 weeks after STZ injection, showed a significant increase in the overall lipid soluble LMWA capacity (p < 0.001). Subsequently, analysis of specific components by high pressure liquid chromatography (electrochemical detection) showed decreased levels of ascorbic acid in plasma, kidney, heart and brain of diabetic animals. The α-tocopherol level dropped in all tissues, except for the liver in which there was a significant increase (p < 0.01 and p < 0.001 at 2–4 weeks). Lipid peroxidation was assessed by conjugated diene levels, which increased significantly in all diabetic tissues except the liver. Insulin treatment that was started after 3 weeks of diabetes and continued for 3 weeks showed no change in the conjugated dienes and in the overall LMWA capacity in all organs. Our results suggest a unique behavior of the liver in the STZ-induced diabetic rats to the stress and indicate its higher capacity to cope with oxidative stress as compared to other organs.     

Antioxidant activity of costunolide and eremanthin isolated from Costus speciosus (Koen ex. Retz) Sm.

Antioxidant properties of many medicinal plants have been widely recognized and some of them have been commercially exploited. Plant derived antioxidants play a very important role in alleviating problems related to oxidative stress. The present study was aimed at assessing the antioxidant property of costunolide and eremanthin isolated from a medicinal plant Costus speciosus (Koen ex. Retz) Sm. rhizome. Experimental diabetes was induced by a single dose of STZ (60 mg/kg, i.p.) injection. The oxidative stress was measured by tissue thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH) content and enzymatic activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) in brain, liver, heart, kidney and pancreas. An increase in TBARS level, a significant reduction in GSH content along with decreased enzymatic activities of SOD, CAT, and GPx were seen in untreated diabetic rats. Administration of either costunolide (20 mg/kg day) or eremanthin (20 mg/kg day) for 60 days caused a significant reduction in TBARS level and a significant increase in GSH content along with increased enzymatic activities of SOD, CAT and GPx in the treated rats when compared to untreated diabetic rats. Acute toxicity test revealed the non-toxic nature of the compounds. The results indicated for the first time the protective effect of costunolide and eremanthin from oxidative stress, thus opening the way for their use in medication.     

Reproduction Is Associated with a Tissue-Dependent Reduction of Oxidative Stress in Eusocial Female Damaraland Mole-Rats (Fukomys damarensis)

Oxidative stress has been implicated as both a physiological cost of reproduction and a driving force on an animal''s lifespan. Since increased reproductive effort is generally linked with a reduction in survival, it has been proposed that oxidative stress may influence this relationship. Support for this hypothesis is inconsistent, but this may, in part, be due to the type of tissues that have been analyzed. In Damaraland mole-rats the sole reproducing female in the colony is also the longest lived. Therefore, if oxidative stress does impact the trade-off between reproduction and survival in general, this species may possess some form of enhanced defense. We assessed this relationship by comparing markers of oxidative damage (malondialdehyde, MDA; protein carbonyls, PC) and antioxidants (total antioxidant capacity, TAC; superoxide dismutase, SOD) in various tissues including plasma, erythrocytes, heart, liver, kidney and skeletal muscle between wild-caught reproductive and non-reproductive female Damaraland mole-rats. Reproductive females exhibited significantly lower levels of PC across all tissues, and lower levels of MDA in heart, kidney and liver relative to non-reproductive females. Levels of TAC and SOD did not differ significantly according to reproductive state. The reduction in oxidative damage in breeding females may be attributable to the unusual social structure of this species, as similar relationships have been observed between reproductive and non-reproductive eusocial insects.     

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

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

Hypoxia and recovery perturb free radical processes and antioxidant potential in common carp (Cyprinus carpio) tissues

The effects of hypoxia exposure and subsequent normoxic recovery on the levels of lipid peroxides (LOOH), thiobarbituric acid reactive substances (TBARS), carbonylproteins, total glutathione levels, and the activities of six antioxidant enzymes were measured in brain, liver, kidney and skeletal muscle of the common carp Cyprinus carpio. Hypoxia exposure (25% of normal oxygen level) for 5h generally decreased the levels of oxidative damage products, but in liver TBARS content were elevated. Hypoxia stimulated increases in the activities of catalase (by 1.7-fold) and glutathione peroxidase (GPx) (by 1.3-fold) in brain supporting the idea that anticipatory preparation takes place in order to deal with the oxidative stress that will occur during reoxygenation. In liver, only GPx activity was reduced under hypoxia and reoxygenation while other enzymes were unaffected. Kidney showed decreased activity of GPx under aerobic recovery but superoxide dismutase (SOD) and catalase responded with sharp increases in activities. Skeletal muscle showed minor changes with a reduction in GPx activity under hypoxia exposure and an increase in SOD activity under recovery. Responses by antioxidant defenses in carp organs appear to include preparatory increases during hypoxia by some antioxidant enzymes in brain but a more direct response to oxidative insult during recovery appears to trigger enzyme responses in kidney and skeletal muscle.     

The effects of exhaustive exercise on the activity levels of catalase in various tissues of male and female rats

The effects of exhaustive exercise on the activity levels of catalase (EC 1.11.1.6) in various tissues of male and female Sprague-Dawley rats (Rattus norvegicus) were investigated. Both the male and female rats were subdivided into an experimental group and a control group consisting of eight rats each. One group of each sex was subjected to a swimming session of 1 h (experimental group) while the other group of each sex served as sedentary control groups. The tissues investigated were liver, heart, kidney and lung. The activity levels of catalase in all the tissues investigated were significantly (P< 0.05) elevated in both male and female rats as a result of exercise. The average increase in the activity levels of catalase in the various tissues investigated for both male and female rats was 417% (males 404%; females 430%). The male and female rats exhibited comparable activity levels of catalase in all the tissues investigated. The higher activity levels of catalase as a result of exercise might be indicative of a compensatory measure to counteract the possible detrimental effects associated with oxidative stress.     

Plasma dependent and independent accumulation of betaine in male and female rat tissues

Tissue betaine is an intracellular osmolyte that also provides a store of labile methyl groups. Despite these important biological roles, there are few data regarding tissue betaine content. We measured the betaine concentration of plasma and various tissues (brain, heart, lungs, liver, kidney, spleen, intestine, reproductive tissues, skeletal muscle and skin) in male and female rats and assessed whether there were any gender-specific differences in betaine content or distribution and whether there was any relationship between tissue accumulation and plasma levels. Betaine was highest in the liver and kidney with values ranging from 1.6 to 9.5 mmol/l and 2.0 to 5.4 mmol/l, respectively. Plasma betaine concentrations were significantly lower than tissue levels except in the brain (? 25 % of plasma) and skeletal muscle (similar to plasma). Regression analysis of the combined male and female data revealed a significant plasma-related accumulation of betaine in the heart, skin and skeletal muscle, while the lung, liver, kidney, spleen, and intestine showed significant plasma-related and plasma-independent accumulations of betaine. The betaine content of the skin, liver and kidney was not significantly different between males and females, but in plasma and all tissues analyzed it was significantly higher in males (P<0.01).     

THE EFFECTS OF EXHAUSTIVE EXERCISE ON THE ACTIVITY LEVELS OF CATALASE IN VARIOUS TISSUES OF MALE AND FEMALE RATS

The effects of exhaustive exercise on the activity levels of catalase (EC 1.11.1.6) in various tissues of male and female Sprague—Dawley rats (Rattus norvegicus) were investigated. Both the male and female rats were subdivided into an experimental group and a control group consisting of eight rats each. One group of each sex was subjected to a swimming session of 1h (experimental group) while the other group of each sex served as sedentary control groups. The tissues investigated were liver, heart, kidney and lung. The activity levels of catalase in all the tissues investigated were significantly (P< 0.05) elevated in both male and female rats as a result of exercise. The average increase in the activity levels of catalase in the various tissues investigated for both male and female rats was 417% (males 404%; females 430%). The male and female rats exhibited comparable activity levels of catalase in all the tissues investigated. The higher activity levels of catalase as a result of exercise might be indicative of a compensatory measure to counteract the possible detrimental effects associated with oxidative stress.