Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P17174 (aspartate aminotransferase)
 14,872 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cocaine produces hepatotoxicity by a mechanism that remains undefined but that has been linked to its oxidative metabolism. Endotoxin (lipopolysaccharide, LPS) is also a well-known cause of hepatic damage, where exposure to non-injurious doses of LPS increases the toxicity of certain hepatotoxins. This study was conducted to investigate the possible potentiation of cocaine-mediated hepatotoxicity (CMH) by LPS. Male CF-1 mice were administered oral cocaine hydrochloride for 5 consecutive days at a dose of 20 mg/kg with and without 12 x 10(6) EU LPS/kg given intraperitoneally 4 h after the last cocaine injection. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured as markers of liver injury. Blood and liver glutathione (GSH) levels were determined, as well as the activities of glutathione peroxidase (GPx) and catalase (CAT). In addition, the activity of liver glutathione reductase (GRx) was measured. The results demonstrate that endotoxin potentiated the hepatotoxicity of cocaine. Serum ALT and AST were significantly elevated with the combined cocaine and LPS treatment versus all other treatments. While cocaine alone resulted in centrilobular necrosis, the cocaine and LPS combination produced submassive necrosis. The increased hepatic GSH content and GRx activity observed with cocaine alone were not observed with the combination treatment, rendering the liver more susceptible to oxidative stress. Moreover, there was a significant decrease in the activities of hepatic GPx and CAT, particularly with the combination treatment. In conclusion, this study demonstrates that LPS potentiates the hepatotoxicity of cocaine as revealed by an array of biochemical and morphological markers.
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PMID:Endotoxin potentiates the hepatotoxicity of cocaine in male mice. 1213 32

The oxidative metabolism of cocaine by the microsomal monooxygenase enzymes has been postulated to be essential for cocaine mediated hepatotoxicity (CMH). Endotoxin (lipopolysaccharide, LPS), a well-known cause of hepatic damage, previously has been demonstrated to dramatically increase CMH. The mechanism of this interaction has not been clearly elucidated, but cocaine oxidative metabolism appears to sensitize hepatocytes so that subsequent exposure to small amounts of LPS can further augment CMH. This study was conducted to investigate if dimethylaminoethyl-2,2-diphenylvalerate (SKF-525A) pretreatment inhibits LPS potentiation of CMH. For 5 consecutive days, male CF-1 mice were administered daily SKF-525A (50 mg/kg) or sterile saline followed an hour later by cocaine (20 mg/kg) or sterile saline. Four hours following the last cocaine or saline treatment, the mice were administered sterile saline 12x10(6) EU LPS/kg, i.p. The mice were sacrificed 18 h later by decapitation. Pretreatment with SKF-525A reversed the hepatic injury caused by cocaine alone or cocaine and LPS treatments, as indicated by both histologic evaluation and serum alanine transaminase (ALT) and aspartate transaminase (AST) activities. In particular, SKF-525A completely reversed the effects of cocaine alone on liver and blood reduced gluthathione (GSH), glutathione peroxidase (GPx) and catalase (CAT) and hepatic glutathione reductase (GRx) activities. However, SKF-525A was ineffective against the effect of LPS alone on liver and blood GPx and CAT or on hepatic GSH and GRx, suggesting that these effects were not mediated by cytochrome P450 oxidative metabolism. The pattern of biochemical changes persisting with SKF-525A pretreatment in the LPS and cocaine group resembled those of the LPS alone group. The results suggest that cytochrome P450 oxidative metabolism of cocaine is largely responsible for CMH with potentiation by LPS achieved through a different mechanism involving oxidative stress.
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PMID:Inhibition of cocaine oxidative metabolism attenuates endotoxin potentiation of cocaine mediated hepatotoxicity. 1220 38

Cocaine produces hepatotoxicity by a mechanism that remains undefined but has been linked to its oxidative metabolism. Endotoxin (lipopolysaccharide, LPS) is also a well-known cause of hepatic damage, and exposure to noninjurious doses of LPS increases the toxicity of certain hepatotoxins. Previously it was demonstrated that exposure to noninjurious doses of LPS dramatically increases cocaine-mediated hepatotoxicity (CMH). This study was conducted to investigate whether pretreatment with N-acetylcysteine (NAC), a glutathione (GSH) precursor and an antioxidant agent, inhibits LPS potentiation of CMH. For 5 consecutive days, male CF-1 mice were administered daily oral NAC (200 mg/kg) or sterile saline followed an hour later by cocaine (20 mg/kg) or sterile saline. Four hours following the last cocaine or saline treatment, the mice were administered 12 x 10(6) EU LPS/kg or sterile saline. For the cocaine alone and cocaine and LPS groups, NAC pretreatment significantly decreased serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities with absence of necrotic hepatic lesions, indicating a reduction of liver injury. In addition, in all groups pretreated with NAC, hepatic GSH concentration was significantly increased, as were hepatic and blood glutathione peroxidase (GPx) and catalase (CAT) activities. In conclusion, the results demonstrate that NAC pretreatment exerted a protective effect against LPS potentia-tion of CMH.
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PMID:N-acetylcysteine pretreatment decreases cocaine and endotoxin-induced hepatotoxicity. 1252 69

Benzanthrone (BA) and 3-bromobenzanthrone (3-BBA) are important dye intermediates used in the manufacture of various vat and disperse dyes. BA has been implicated as a cause of hepatic malfunctions and dermal lesions in workers. However, not much information on halogenated BAs, especially 3-BBA, is available. Experiments were designed to undertake a comparative safety assessment of both BA and 3-BBA, given orally at a dose of 50 mg/kg body weight for 10 days to guinea pigs. There was a significant decrease (25%) in body weight with 3-BBA, whereas BA treatment did not cause any change. Serum glutamate oxaloacetate transaminase and glutamate pyruvate transminase were found to be significantly (P<0.05) increased in 3-BBA- as well as in BA-treated animals. 3-BBA and BA led to substantial depletion of ascorbic acid in both liver and adrenal glands. However, depletion of ascorbic acid was more pronounced with 3-BBA (19.2-28.3%) than with BA (13.5-16.6%). 3-BBA and BA treatments caused 80% and 24% depletion of hepatic free sulfydryl content, while lipid peroxidation showed a significant enhancement of 73% and 47%, respectively. BA and 3-BBA caused decreases in cytochrome P-450 content and phase I enzymes particularly ethoxyresorufin- O-deethylase and aryl hydrocarbon hydroxylase, whereas phase II enzymes (quinone reductase and glutathione- S-transferase) were substantially increased. Activities of bio-antioxidant enzymes, viz., glutathione peroxidase, glutathione reductase, superoxide dismutase and catalase, were significantly increased by 153, 104, 20 and 67% in the 3-BBA-treated group, whereas the degree of increase in these parameters was relatively less in BA-treated group. The data indicate that both BA and 3-BBA can disturb membrane integrity by decreasing endogenous glutathione and ascorbic acid levels with a concomitant increase in lipid peroxidative damage. This may in turn lead to impairment of hepatic P-450-dependent monooxygenase, while the changes in antioxidant enzymes reveal oxidative stress. 3-BBA treatment caused dilation of portal triad with thickening of arterial wall, hyperplasia of Kupffer cells and influx of inflammatory cells between hepatic cords, which could be due to formation of Br(*) radical or due to formation of semiquinone type of intermediate following oxidation. The results may be interpreted to mean that industrial workers exposed to 3-BBA are at higher risk than those exposed to BA, and necessary precautions should be taken to safeguard their exposure risks.
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PMID:Comparative effect of benzanthrone and 3-bromobenzanthrone on hepatic xenobiotic metabolism and anti-oxidative defense system in guinea pigs. 1259 Mar 61

In the present study we evaluated the toxicological effects of a scarcely documented environmental pollutant, perfluorooctane sulfonic acid (PFOS), on selected biochemical endpoints in the common carp, Cyprinus carpio. Juvenile organisms were exposed to PFOS through a single intraperitoneal injection (liver concentrations ranging from 16 to 864 ng/g after 5 days of exposure) and after 1 and 5 days effects were assessed in liver and serum of the exposed organisms. The investigation of the hepatotoxicity of PFOS included the determination of the peroxisome proliferating potential (peroxisomal palmitoyl CoA oxidase and catalase activity) and the compounds influence on the average DNA basepair length (ABPL) by agarose gel electrophoresis. Total antioxidant activity (TAA), cholesterol and triglyceride levels were monitored in the serum. After 1 day of exposure the ABPL was significantly increased in the 270 and 864 ng/g treatment groups. After 5 days of exposure significant increases relative to the control were observed for the 16, 270 and 864 ng/g treatment groups. Enzyme leakage from the liver was investigated by measurement of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities in the serum. At 561, 670 and 864 ng/g PFOS a significant increase in serum ALT activity became apparent after 5 days of exposure with values ranging from 159 to 407% relative to the control. For serum AST activity a significant increase for the 864 ng/g treatment group was observed with a value of 112% relative to the control. Determination of the polymorphonuclear leukocyte migration into liver tissue as assessed through myeloperoxidase (MPO) activity in liver, was used as an indicator for inflammation. It appeared that inflammation was not involved in the observed membranous enzyme leakage for the 561, 670 and 864 ng/g PFOS treatment groups. The results of this study suggest that PFOS induces inflammation-independent enzyme leakage through liver cell membranes that might be related to cell necrosis. Furthermore, results show that PFOS does not significantly affects serum antioxidant levels nor does it clearly induce peroxisome proliferation in carp. This study also points out that PFOS might interfere with homeostasis of the DNA metabolism. The results of these biochemical analyses were used to perform an initial hazard assessment study indicating that PFOS levels observed in tissues of wildlife populations could induce a clear rise in serum transaminase levels indicative for disruption of hepatocyte membrane integrity.
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PMID:Evaluation of the toxicological effects of perfluorooctane sulfonic acid in the common carp (Cyprinus carpio). 1259 74

Piper betle L. is a commonly used masticatory in Asia. This study was carried out to investigate the hepatoprotective and antioxidant properties of P. betle, using ethanol intoxication as a model of hepatotoxic and oxidative damage. Ethanol-treated rats exhibited elevation of hepatic marker enzymes and disturbances in antioxidant defense when compared with normal rats. Oral administration of P. betle extract (100, 200, or 300 mg/kg body weight) for 30 days significantly (P <.05) decreased aspartate aminotransferase (AST), alanine aminotransferase (ALT), thiobarbituric acid reactive substances (TBARS), and lipid hydroperoxides in ethanol treated rats. The extract also improved the tissue antioxidant status by increasing the levels of nonenzymatic antioxidants (reduced glutathione, vitamin C, and vitamin E) and the activities of free radical-detoxifying enzymes such as superoxide dismutase, catalase, and glutathione peroxidase in liver and kidney of ethanol-treated rats. The highest dose of P. betle extract (300 mg/kg body weight) was most effective. The results were comparable with the known hepatoprotective drug, silymarin. These results indicate that P. betle could afford a significant hepatoprotective and antioxidant effect.
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PMID:Influence of Piper betle on hepatic marker enzymes and tissue antioxidant status in ethanol-treated Wistar rats. 1263 94

Administration of isoproterenol to mice at a dose of 30 mg/100 g body weight for 3 consecutive days at an interval of 24 h induced lipid peroxidation in cardiac tissue and exhibited a significantly elevated serum glutamate oxaloacetate transaminase (SGOT) level. Increased superoxide dismutase (SOD) activity with a concomitant decrease in catalase activity has also been observed in cardiac tissue with isoproterenol treatment. Quinidine, a class I antiarrhythmic agent has been found to exhibit a protective role in isoproterenol induced myocardial ischaemia. Cardiac tissue of quinidine treated mice showed reduction of lipid peroxidation reaction. In addition, quinidine treatment is found to influence the cardiac antioxidant enzymes - catalase and SOD. The decrease of SOD activity and increase of catalase activity suggests that quinidine also exerts an 'indirect antioxidant' effect in protecting the myocardial tissue from reactive oxygen species. Furthermore, our current in vitro studies with quinidine have clearly shown in this work that it possesses a very convincing hydroxyl radical scavenging potential with almost no ability to scavenge superoxide anion and hydrogen peroxide (H2O2) in vitro. Thus, our present investigation suggests that quinidine, when administered to mice, strengthens the antioxidant defense system to resist the free radical induced damage brought about by isoproterenol induced ischaemic condition.
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PMID:Effect of isoproterenol on lipid peroxidation and antioxidant enzymes of myocardial tissue of mice and protection by quinidine. 1270 43

Antrodia camphorata (A. camphorata) is well-known in Taiwan as a traditional Chinese medicine. The purpose of this study was to evaluate the ability of A. camphorata extracts to protect against oxidative stress in vitro and against carbon tetrachloride (CCl(4))-induced hepatic injury in vivo. An extract of A. camphorata inhibited nonenzymatic iron-induced lipid peroxidation in rat brain homogenates with an IC(50) value about 3.1 mg/mL. It also scavenged the stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH). The dose of the A. camphorata extract resulting in a decrease of 0.20 in the absorbance of DPPH was about 31 +/- 0.7 microg/mL. Furthermore, an A. camphorata extract dose-dependently (250-1250 mg/kg) ameliorated the increase in plasma aspartate aminotransferase (GOT) and alanine aminotransferase (GPT) levels caused by chronic repeated CCl(4) intoxication in mice. Moreover, A. camphorata extract significantly improved the CCl(4)-induced increase in hepatic glutathione peroxidase, reductase, and CCl(4)-induced decrease in superoxide dismutase activities. It also restored the decrement in the glutathione content and catalase activity of hepatic tissues in CCl(4)-intoxicated mice. Furthermore, it also dose-dependently inhibited the formation of lipid peroxidative products during CCl(4) treatment. Histopathological changes of hepatic lesions induced by CCl(4) were significantly ameliorated by treatment with an A. camphorata extract in a dose-dependent manner. These results suggest that A. camphorata extract exerts effective protection against chronic chemical-induced hepatic injury in vivo, by mediating antioxidative and free radical scavenging activities.
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PMID:Antioxidative and hepatoprotective effects of Antrodia camphorata extract. 1274 58

Free radicals and oxidative stress have been implicated in the etiology of diabetes and its complications. This in vivo study has examined whether subacute administration of pycnogenol, a French pine bark extract containing procyanidins that have strong antioxidant potential, alters biomarkers of oxidative stress in normal and diabetic rats. Diabetes was induced in female Sprague-Dawley rats by a single injection of streptozotocin (90 mg/kg body weight, ip), resulting (after 30 days) in subnormal body weight, increased serum glucose concentrations, and an increase in liver weight, liver/body weight ratios, total and glycated hemoglobin, and serum aspartate aminotransferase activity. Normal and diabetic rats were treated with pycnogenol (10 mg/kg body weight/day, ip) for 14 days. Pycnogenol treatment significantly reduced blood glucose concentrations in diabetic rats. Biochemical markers for oxidative stress were assessed in the liver, kidney, and heart. Elevated hepatic catalase activity in diabetic rats was restored to normal levels after pycnogenol treatment. Additionally, diabetic rats treated with pycnogenol had significantly elevated levels of reduced glutathione and glutathione redox enzyme activities. The results demonstrate that pycnogenol alters intracellular antioxidant defense mechanisms in streptozotocin-induced diabetic rats.
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PMID:Effects of pycnogenol treatment on oxidative stress in streptozotocin-induced diabetic rats. 1281 16

Increased oxidative stress and impaired antioxidant defense mechanisms are important factors in the pathogenesis and progression of diabetes mellitus and other oxidant-related diseases. This study was designed to determine whether alpha-lipoic acid, which has been shown to have substantial antioxidant properties, when administered (10 mg/kg ip) once daily for 14 days to normal and diabetic female Sprague-Dawley rats would prevent diabetes-induced changes in biomarkers of oxidative stress in liver, kidney and heart. Serum glucose concentrations, aspartate aminotransferase activity, and glycated hemoglobin levels, which were increased in diabetes, were not significantly altered by alpha-lipoic acid treatment. Normal rats treated with a high dose of alpha-lipoic acid (50 mg/kg) survived but diabetic rats on similar treatment died during the course of the experiment. The activity of glutathione peroxidase was increased in livers of normal rats treated with alpha-lipoic acid, but decreased in diabetic rats after alpha-lipoic acid treatment. Hepatic catalase activity was decreased in both normal and diabetic rats after alpha-lipoic acid treatment. Concentrations of reduced glutathione and glutathione disulfide in liver were increased after alpha-lipoic acid treatment of normal rats, but were not altered in diabetics. In kidney, glutathione peroxidase activity was elevated in diabetic rats, and in both normal and diabetic animals after alpha-lipoic acid treatment. Superoxide dismutase activity in heart was decreased in diabetic rats but normalized after treatment with alpha-lipoic acid; other cardiac enzyme activities were not influenced by either diabetes or antioxidant treatment. These results suggest that after 14 days of treatment with an appropriate pharmacological dose, alpha-lipoic acid may reduce oxidative stress in STZ-induced diabetic rats, perhaps by modulating the thiol status of the cells.
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PMID:Effects of alpha-lipoic acid on biomarkers of oxidative stress in streptozotocin-induced diabetic rats. 1283 33


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