Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.6.1.2 (alanine aminotransferase)
26,722 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mechanisms of chronic cocaine toxicity and its potentiation by ethanol were investigated. Cocaine was administered to male C57BL/6 mice (20 mg/kg by peritoneal injection twice a day) alone or in combination with ethanol-containing diets (26% of total calories) supplied with a normal (20 IU/liter) or high content (170 IU/liter) of vitamin E. Liver levels of vitamin E, reduced glutathione, ascorbic acid, and hydroxyproline were measured. Accumulation of thiobarbituric acid-reactive substances, after in vitro stimulation of lipid peroxidation by Fe3+/ADP/ascorbate system, was measured as an index of susceptibility of hepatic membranes to oxidative stress. Plasma alanine aminotransferase, lethality, liver weight, and liver/body weight ratio were determined to assess the extent of liver toxicity. Consumption of ethanol exacerbated liver toxicity induced by cocaine treatments and reduced survival, but ethanol or cocaine treatments alone caused no or only modest mortality. Ethanol potentiated cocaine-induced accumulation of collagen in the liver and depletion of ascorbic acid. Hepatotoxicity induced by the combined ethanol plus cocaine treatment was not accompanied by a decrease in intracellular vitamin E or glutathione content. There were no changes in the basic levels and in the rate of accumulation of thiobarbituric acid-reactive substances in liver homogenates under the lipid peroxidation-stimulating system in vitro. The toxic effects of ethanol and cocaine were not reduced by the ingestion of vitamin E during short-term exposure of 21 days of treatment.
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PMID:Chronic ethanol and cocaine-induced hepatotoxicity: effects of vitamin E supplementation. 144 28

The influence of 5,10-dihydroindeno[1,2-b]indole (indenoindole) on carbon tetrachloride (CCl4)-mediated hepatotoxicity and lipid peroxidation were examined. Indenoindole (25 mg/kg body weight) ameliorated the increase in liver enzymes appearing in the plasma 24 hr after CCl4 administration, with about a 63% reduction for alanine transaminase, 56% for ornithine transcarbamylase and 84% for alkaline phosphatase. Indenoindole also partially prevented, in a dose-dependent fashion, the decrease in hepatic cytochromes P-450, total tissue reducing equivalents and hepatic ascorbate levels resulting 4 hr after CCl4 administration. In a homogeneous chemical system consisting of purified soybean phospholipid substrate in chlorobenzene, azobisisobutyronitrile-initiated lipid peroxidation was inhibited by indeno-indole, with 50% inhibition occurring at about 17 microM. Inhibition by indenoindole of iron-ascorbate-initiated lipid peroxidation in aqueous buffer containing phospholipid vesicles was about tenfold more efficient, with 50% inhibition occurring at about 1.5 microM. Presumably, this was due to the increased concentration of indenoindole in the membrane of the phospholipid vesicle. The efficiency of inhibition of lipid peroxidation was in the order of indenoindole = butylated hydroxytoluene (BHT) greater than alpha-tocopherol much greater than indole greater than indene. These 50% inhibition values of lipid peroxidation for these compounds were similar in an assay system composed of NADPH-fortified mouse-liver microsomes initiated with CCl4. For indenoindole, the 50% inhibition value (1.3 microM) was more than two orders of magnitude less than the spectral binding constant for indenoindole to mouse-liver cytochrome P-450 (Kd = 236 microM), implying that the partial inhibition of metabolic activation of CCl4 was not responsible for the inhibition of lipid peroxidation observed with indenoindole in this system. It appears that indenoindole may trap reactive radicals and inhibit lipid peroxidation in vitro. Regardless of whether inhibition is at the level of scavenging CCl4 metabolite radicals, or lipid radicals in membranes, radical trapping provides a plausible mechanism by which this compound inhibited CCl4 hepatotoxicity.
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PMID:Protection against carbon tetrachloride hepatotoxicity by 5,10-dihydroindeno[1,2-b]indole, a potent inhibitor of lipid peroxidation. 316 51

The cytoprotective effect of the natural dietary constituent indole-3-carbinol (I-3-C) on carbon tetrachloride (CCl4) mediated hepatotoxicity in mice was examined. I-3-C pretreatment by gavage 1 hr prior to intraperitoneal injection of CCl4 produced a 63% decrease in CCl4-mediated centrolobular necrosis and a related 60% decrease in plasma alanine aminotransferase activity (a marker of liver necrosis). Since the toxicological effects of CCl4 are mediated by radical species generated during reductive metabolism by cytochrome P-450, we examined the potential ability of I-3-C to scavenge reactive radicals. Three systems were used to evaluate the ability of I-3-C to intervene in free radical mediated lipid peroxidation. These systems consisted of the following: (1) phospholipid dissolved in chlorobenzene, with peroxidation initiated by the thermal and photo decomposition of azobisisobutyronitrile (AIBN); (2) sonicated phospholipid vesicles in phosphate buffer (pH 7.4), with peroxidation initiated by ferrous/ascorbate; and (3) mouse liver microsomes containing an NADPH-regenerating system, with peroxidation initiated with CCl4. Lipid peroxidation was measured in these three systems as thiobarbiturate-reacting material. In the AIBN and ferrous/ascorbate systems, I-3-C inhibited lipid peroxidation, with greater inhibition under conditions of low rates of free radical generation. I-3-C was not as effective an antioxidant as butylated hydroxytoluene (BHT) or tocopherol, but it inhibited peroxidation in a dose-response manner. I-3-C was most effective as a radical scavenger in the microsomal CCl4-initiated system by inhibiting lipid peroxidation in a dose-dependent fashion, with 50% inhibition at 35-40 microM I-3-C. This concentration is about one-third of the concentration of I-3-C achieved in liver after treatment of mice by gavage with 50 mg I-3-C/kg body weight. These data suggest that I-3-C may be a natural antioxidant in the human diet and, as such, may intervene in toxicological or carcinogenic processes that are mediated by radical mechanisms.
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PMID:Intervention in free radical mediated hepatotoxicity and lipid peroxidation by indole-3-carbinol. 334 90

A novel assay system was developed in order to quantitate the nucleophilicity of pure chemicals or tissue extracts. This Nucleophilic Index Value (NIV) assay was based on the ability of putative nucleophiles to inhibit the methylation of cysteine by limiting concentrations of the electrophilic source, N-methyl-N-nitrosourea (MNU). Efficacy of model and cellular nucleophiles was quantitated as nmol cysteine protected by the nucleophile from methylation by MNU/h/mM compound. The NIVs of the pure compounds ascorbate, glutathione, 4-(4-nitrobenzyl)-pyridine (NBP) and indole-3-carbinol (I-3-C) were 2400, 1600, 3 and 0, respectively. When mice were treated with I-3-C by gavage at dosages of 0, 25, 50, 75 or 100 mg/kg body wt, the NIV for ethyl acetate extracts of the livers 1 h after treatment were 0, 33, 47, 52 and 92 nmol cysteine preserved/h/g tissue, respectively. The I-3-C enhancement of NIV was not attributable to ascorbate or glutathione, neither of which were present in the ethyl extracts of liver. When mice were treated with 10 mg N-nitrosodimethylamine (NDMA)/kg body wt 1 h after the varying dosages of I-3-C, the 24 h post-NDMA plasma alanine transaminase (ALT) values were decreased by I-3-C pretreatment in a dose-dependent fashion. Plasma ALT values were used in this study as an indicator of hepatotoxicity. The coefficient of determination, r2, computed from the linear least squares correlation coefficient between NIV and ALT values, was 0.80 (0-100 mg I-3-C/kg) and 0.97 (0-75 mg/kg).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Nucleophilic index value: implication in the protection by indole-3-carbinol from N-nitrosodimethylamine cyto and genotoxicity in mouse liver. 337 33

The metabolism of vitamin C and the function of the liver were investigated in 106 patients suffering from alcoholism (34 with clinical stage 1, 53 with clinical stage 2, and 19 with alcoholic delirium). The levels of ascorbic acid (AA) were reduced while those of dehydroascorbic (DAA) and diketogulonic acids (DKGA) were elevated. Red blood cells presented an increase in both AA and DAA and a decrease in DKGA concentrations. AA excretion with the urine was diminished. Considerable liver dysfunction was ascertained. Intensity of the normalization of AA metabolism coincided in time with the normalization of liver enzyme levels (ALT, AsT, CE). Degree of changes in AA metabolism in alcoholism may to a certain degree depend on the severity of liver dysfunction.
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PMID:[Features of vitamin C metabolism and the functional status of the liver in alcoholism and alcoholic delirium in the stage of detoxification therapy]. 357 14

Indole-3-carbinol (I-3-C) was examined for its ability to protect mice against 24-hr N-nitrosodimethylamine (NDMA)-mediated hepatotoxicity. NDMA (20 mg/kg body weight) alone produced extensive hemorrhagic and centrolobular necrotic lesions, with a necrotic severity index of 3.0 +/- 0.4 (scale of 0-5). Treatment with 50 mg/kg body weight of I-3-C by gavage, 1 hr prior to NDMA, substantially protected against hemorrhagic lesions. Furthermore, I-3-C lowered the NDMA-mediated tissue necrotic index to 1.5 +/- 0.3, by reducing the extent of tissue necrosis rather than the severity in the necrotic region. Release of liver enzymes into the blood correlated with the histopathology; I-3-C reduced NDMA-mediated elevated activities of plasma alanine transaminase and ornithine transcarbamylase by 84 and 51.3%, respectively. Although no changes in nonprotein sulfhydryls were evident at 24-hr after NDMA, ascorbate levels were reduced to 40% of control values. However, treatment with I-3-C prior to NDMA prevented the decline in tissue ascorbate concentrations. In vitro, I-3-C was found to be a type II ligand for cytochrome P-450, with a Ks value of 237 microM. However, if such binding occurs in vivo, it does not protect against the approximately 60% decrease in hepatic cytochrome P-450 or the 80% decrease in NDMA demethylase I activity produced by NDMA. Since I-3-C slightly enhances cytochrome P-450 content and NDMA demethylase activity, the histopathologic protection by I-3-C must be due to factors other than inhibiting metabolic activation of NDMA.
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PMID:Protection from N-nitrosodimethylamine-mediated liver damage by indole-3-carbinol. 365 48

Protection against the toxic effects of chronic alcohol consumption was observed in male guinea pigs maintained on a high-ascorbic-acid diet (vitamin C-deficient chow plus 2.0 mg ascorbic acid/ml drinking water) as compared to animals on a low-ascorbic-acid diet (vitamin C-deficient chow and from 0.025 to 0.050 mg ascorbic acid/ml drinking water). Alcohol was orally administered to the guinea pigs at a dose of 2.5 g/kg for up to 14 weeks. Levels of serum aspartate aminotransferase and serum alanine aminotransferase were significantly elevated in animals on the low-ascorbic-acid diet that received alcohol, 120 and 250%, respectively. In contrast, in animals on the high-ascorbic-acid diet that received alcohol, levels of alanine aminotransferase were not significantly elevated and levels of aspartate aminotransferase were elevated 50%. In addition, some of the animals on the low-ascorbic-acid diet that received alcohol for 12 to 14 weeks developed hepatic steatosis and necrosis, whereas none of the animals on the high-ascorbic-acid diet that received alcohol for the same length of time manifested these changes.
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PMID:Ascorbic acid chronic alcohol consumption in the guinea pig. 371 80

The oral treatment of rats with sodium ascorbate in combination with sodium nitrite and aminopyrine prevents the rise in serum alanine aminotransferase (EC 2.6.1.2) observed when nitrite and aminopyrine are given alone. Ascorbic acid also affords protection, whereas dehydroascorbic acid exerts no protective effect.
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PMID:Protective effect of ascorbic acid on hepatotoxicity caused by sodium nitrite plus aminopyrine. 451 87

Sex- and age-related differences in dietary and blood chemistry factors were investigated in subjects adhering to their usual lifestyles. Diet records were examined daily and blood chemistry profiles were monitored five times during the 1-yr study. As expected, high-density lipoprotein cholesterol was significantly higher in women than in men. Values of creatine phosphokinase, aspartic aminotransferase, alanine aminotransferase, glucose, triglycerides, urea nitrogen, uric acid, and total bilirubin were higher in men than in women. Glucose was lower while high-density lipoprotein cholesterol, albumin, and total protein were higher in the younger women than in older women. Alcohol consumption by men correlated positively with aspartic aminotransferase and alanine aminotransferase but not with high-density lipoprotein cholesterol. Alcohol consumption by women did correlate positively with high-density lipoprotein cholesterol but not with the aminotransferase enzymes. Correlations between serum high-density lipoprotein cholesterol and vitamin C intake were positive and significant in women. In men, high levels of high-density lipoprotein cholesterol seems to be associated with very high vitamin C intakes, but no associations were apparent at normal levels of these parameters. Serum cholesterol did not correlate significantly with dietary cholesterol, saturated fat, linoleic acid, or P/S in men or women.
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PMID:Relationships among dietary constituents and specific serum clinical components of subjects eating self-selected diets. 650 55

Relationships between serum thiobarbituric acid (TBA) level and smoking, alcohol drinking, differences in food intake with alcohol drinking, serum vitamin C (VC) and E (VE) were studied in 283 non-treated men (aged 20-69 years) who visited a human dock conducted in an urban area of Hyogo prefecture in 1989-1991 (annually May-July). The results were as follows: 1. An effect of smoking on serum TBA level was not observed. 2. The subjects were divided into three groups according to weekly sake intake levels, i.e., non-drinkers including ex-drinkers (ND), mild drinkers (MD, weekly sake intake: < or = 1260 ml), and heavy drinkers (HD, > 1260 ml). The serum TBA level of HD, but not of MD, was significantly higher than that of ND. 3. Serum TBA level had significant positive correlations with age, GPT, gamma-GTP, TC (total cholesterol), TG (triglycerides), PL (phospholipids), total serum lipids (TLP, i.e., TC+TG+PL), VE, eicosapentaenoic acid (EPA, C20:5) and docosahexaenoic acid (DHA, C22:6), but had no significant correlations with VC and VE/TLP. 4. The subjects (N+M) D, which included ND and MD, and those of HD were divided respectively into three groups according to weekly food intake levels, i.e., non-intake group (NF), low frequent intake group (LF, 1-3 days/week), and high frequent intake group (HF, > or = 4 days/week). The fish intake level of HD was significantly higher than that of (N+M) D, while the intake levels of vegetables, fruits and soft drinks of HD were significantly lower than those of (N+M) D. 5. Serum TBA level, GOT, GPT, gamma-GTP, TG, PL, TLP, VE, EPA and DHA of HD were significantly higher than those of (N+M) D. On the other hand, VC of HD was significantly lower than that of (N+M) D. 6. When the subjects of (N+M) D were divided into three groups according to weekly fish intake levels as mentioned above, serum TBA level, EPA and DHA of HF in (N+M) D were significantly higher than those of NF in (N+M) D. 7. Serum TBA level of HD in non-fish intake group was significantly higher than that of (N+M) D in the same group. These results suggest that increased serum TBA level in HD is closely related to the increased intake frequency of fish in addition to the effect of alcohol drinking.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Relationships between serum lipid peroxide level (serum TBA level) and smoking, alcohol drinking, food frequency, serum vitamin C and E in subjects with multiphasic screening]. 802 8


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