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:2.6.1.1 (aspartate aminotransferase)
21,665 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fluvastatin, a new synthetic inhibitor of HMGCoA (3-hydroxy-3-methylglutaryl coenzyme A) reductase, has been studied in several models to examine its effects when used in combination with other lipid-modifying agents such as derivatives of fibric acid (bezafibrate), resins (cholestyramine), and niacin. The combination of fluvastatin with bezafibrate has been studied in a double-blind trial involving patients with well-documented familial hypercholesterolaemia. Fluvastatin 40 mg/day, combined with either bezafibrate 400 mg/day or cholestyramine 8 g/day, resulted in reductions in levels of low-density lipoprotein cholesterol (LDL-C), these being indistinguishable between the groups; however, significantly greater increases in levels of high-density lipoprotein cholesterol (21.3%) and reductions in levels of triglycerides (25.1%) were seen with the fluvastatin-bezafibrate combination. No notable increases were seen in levels of serum creatine kinase, aspartate aminotransferase, or alanine aminotransferase, and no cases of myopathy were observed. In a study model that examined low-dose combinations of fluvastatin with cholestyramine, reductions in levels of LDL-C of 15.8% and 19.3% were seen with fluvastatin 10 mg and 20 mg, respectively. After an 8-week interval in which a daily dosage of cholestyramine 8 g was added, from baseline, reductions of 26.3% in the 10 mg fluvastatin-cholestyramine group and 31.2% in the 20 mg fluvastatin-cholestyramine group were observed, whereas the placebo-cholestyramine group displayed a reduction of 14.9%. Doubling the resin dosage to 16 g/day for the final 8 weeks of the study provided little additional benefit. Myotoxicity has been observed when lovastatin is coadministered with niacin, and so the combination of niacin with fluvastatin has also been studied to examine the possibility of this effect occurring. Patients were randomised to either fluvastatin 20 mg or placebo for 6 weeks, after which time open-label niacin was administered to all patients and titrated to a final dosage of 3 g/day. After 6 weeks, fluvastatin produced a 20.8% reduction in LDL-C levels from baseline. When combined with niacin, a 43.7% reduction was noted at the week 15 endpoint, against the 26.5% reduction seen with niacin monotherapy. The combination was well tolerated, with no reports of myopathy or of significant elevations in creatine kinase or liver transaminase levels. Combinations of fluvastatin with a variety of other agents have been shown to have significant effects on lipid profiles, with no evidence to date of clinically remarkable safety findings. Thus, the use of combination therapies may result in optimal management of patients with moderately severe hypercholesterolaemia and mixed dyslipidaemic profiles.
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PMID:Fluvastatin in combination with other lipid-lowering agents. 1949 70

The toxicity of atorvastatin (AT), an inhibitor of hydroxymethylglutaryl-coenzyme A reductase (HMG), was evaluated in beagle dogs. In 4 studies [2-wk rising dose (daily increasing doses for 1 wk; maintenance for 1 wk), 12-wk rising dose (daily dosing with weekly increases in dose), 2-wk toxicity (daily dosing for 2 wk; 3 dose levels), 13-wk toxicity (daily dosing for 13 wk; 3 dose levels)], dogs received up to 400 mg/kg orally. Doses of 180 mg/kg induced moribundity, necessitating euthanasia. Weight losses up to 26% were seen at doses > or = 150 mg/kg. Decreases in cholesterol levels were dose-related. Alanine and/or aspartate aminotransferase were increased at doses > or = 80 mg/kg; alkaline phosphatase was increased at doses > or = 150 mg/kg. Histopathologic findings were seen at > or = 150 mg/kg and included hepatocellular eosinophilia related to increased smooth endoplasmic reticulum and cholangiohepatitis and cholecystitis at 150 mg/kg in the 2-wk toxicity study; hepatocellular degeneration, centrilobular bridging, cholecystitis, hemorrhage in gallbladder and brain, demyelination of optic nerve, and skeletal muscle necrosis at > or = 280 mg/kg in the 12-wk rising dose study; and erosion and hemorrhage in large intestine, hepatocellular degeneration and necrosis, and inflammation and necrosis of gallbladder epithelium at 320 mg/kg in the 2-wk rising dose study. Doses up to 80 mg/kg for 13 wk did not induce histopathologic lesions in examined organs. AT effectively lowered serum cholesterol in normal lipidemic dogs. Toxicity at AT in dogs was similar to that with other inhibitors of HMG except that lenticular changes were not seen, significant hepatic, testicular, or neurological toxicity was associated only with high doses at AT, and skeletal muscle changes similar to those described in rats and rabbits were identified.
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PMID:Subchronic toxicity of atorvastatin, a hydroxymethylglutaryl-coenzyme A reductase inhibitor, in beagle dogs. 886 88

We found that NADPH-dependent ubiquinone reductase (NADPH-UQ reductase) in rat liver cytosol reduces ubiquinone (UQ) to ubiquinol (UQH2) in lipid membranes and consequently inhibits lipid peroxidation [Takahashi T., et al., Biochem. J., 309, 883-890 (1995)]. Here we examined whether or not this UQH2-regenerating system functions as a cellular antioxidant defense in animals. Rats were given UQ-10 for 2 weeks, and were then exposed to carbon tetrachloride (CCl4). The UQ-10 supplement increased only in the NADPH-UQ reductase and the UQH2-10 pool of rat liver without any appreciable change in the levels of other antioxidant factors. On the other hand, CCl4 markedly increased plasma aspartate aminotransferase and alanine aminotransferase, liver weight and thiobarbituric acid reacting substances formation, which are indicators of CCl4-hepatitis, and it decreased the liver levels of L-ascorbic acid, reduced form of glutathione (GSH), alpha-tocopherol, NADPH-UQ reductase and glutathione S-transferase. However, all the above indicators of CCl4-induced hepatitis were significantly improved in rats given UQ-10. Furthermore, alpha-tocopherol, but neither L-ascorbic acid nor GSH, was significantly saved. UQ-10 supplement also was recovered glutathione S-transferase and NADPH-UQ reductase activities slightly. These results indicated that UQ-10 given to rats increased the cellular UQH2-10 pool and cytosolic NADPH-UQ reductase activity in their livers, resulting in the inhibition of lipid peroxidation in the biomembranes, and consequently protected the rats from the CCl4-hepatotoxicity.
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PMID:Cellular antioxidant defense by a ubiquinol-regenerating system coupled with cytosolic NADPH-dependent ubiquinone reductase: protective effect against carbon tetrachloride-induced hepatotoxicity in the rat. 887 5

Experimentally induced lead poisoning especially under simultaneous iron deficit leads to the development of secondary thiamine insufficiency. Erythrocyte riboflavin content and erythrocyte glutathion reductase and aspartate aminotransferase activities have been demonstrated to be increased. Lead treatment is accompanied with the increase of urinary excretion of riboflavin, 4-pyridoxic acid and 1-vtthylnicotinamide in rats fed with adequate diet. Thus lead intoxication and iron deficiency influence vitamin B group metabolism.
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PMID:[Influence of lead on metabolism of vitamins B group in alimentary iron deficient rats]. 927 79

Effects of a single dose of betaine on the chloroform-induced hepatotoxicity were examined in adult male ICR mice. Administration of betaine (1000 mg/kg, ip) 1 to 7 hr prior to a chloroform challenge (0.25 ml/kg, ip) resulted in remarkable enhancement of hepatotoxicity as indicated by increases in serum sorbitol dehydrogenase (SDH), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities. The potentiation of hepatotoxicity was most significant when mice were treated with betaine 4 hr earlier than chloroform. However, a 24 hr prior administration of betaine protected the animals from induction of the chloroform hepatotoxicity. Thus, its effect appeared to be highly dependent on the time lapse from the betaine pretreatment to the challenge of mice with chloroform. Betaine treated either 4 or 24 hr prior to sacrifice did not alter the hepatic contents of cytochrome P-450, cytochrome b5, or NADPH cytochrome P-450 reductase activity. Accordingly the hepatic microsomal p-nitroanisole O-demethylase, aminopyrine N-demethylase, or p-nitrophenol hydroxylase activities were not influenced by the betaine pretreatment. Betaine was shown not to affect any of the enzyme activities associated with glutathione (GSH) conjugation reaction, such as glutathione S-transferases (GSTs), glutathione disulfide (GSSG) reductase and GSH peroxidase irrespective of the time of its administration. When betaine was administered to mice 2-6 hr prior to sacrifice, hepatic GSH level, but not plasma GSH, was decreased significantly. Enhancement of the chloroform hepatotoxicity by betaine correlated well with the reduction in hepatic GSH levels. Both hepatic and plasma GSH levels were elevated in mice 24 hr following the betaine treatment. The results suggest that betaine affects induction of the chloroform hepatotoxicity by modulating the availability of hepatic GSH, which appears to be associated with its role in the transsulfuration pathway in the liver.
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PMID:Effects of singly administered betaine on hepatotoxicity of chloroform in mice. 973 16

Renal and hepatic subacute toxicity induced by the antihyperlipidaemic drugs: Bezalip-Pravastatin and Lopid was investigated in rats using serum biochemical parameters. Toxicological evaluation was performed in serum samples following the administration of the therapeutic dose regimens of the compounds that were previously shown to be effective in inhibition of 3-hydroxy-methylglutaryl coenzyme A (HMG CoA) reductase, the enzyme controlling the rate-limiting step in the synthesis of cholesterol, and acyl-CoA cholesterol acyl transferase (ACAT) which converts intracellular free cholesterol to cholesterol ester. Renal and hepatic subacute toxicity was evaluated by measuring enzyme activity or concentrations of: alanine aminotransferace, alkaline phosphatase, aspartate aminotransferase, gamma-glutamyltransferase, glucose, potassium, sodium, blood urea nitrogen, uric acid and creatinine. The use of the above serum biochemical parameters indicated that the overall toxicity impact of antihyperlipidaemic drugs was Bezalip = Pravastatin < Lopid. We have found that the Pravastatin--in contrast to the above antihyperlipidaemic drugs--only transiently affects the biochemical parameters associated with toxicity, but, it affects some of the biochemical parameters associated with hepatic and renal toxicity, up to a significantly lower extent than the antihyperlipidaemic drugs.
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PMID:Evaluation of kidney and liver subacute toxicity induced by Bezalip-Pravastatin-Lopid antihyperlipidaemic compounds in rats. 1020 89

This study investigated the potential alteration in the amount of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase messenger RNA (mRNA) and lipoprotein lipase (LPL) mRNA in the livers of C57BL/6 mice after long-term (200 days) treatment with the nonionic surfactant called poloxamer 407 (P-407). Previously, P-407 has been used to produce a dose-controlled hyperlipidemic state in C57BL/6 mice with subsequent formation of atherosclerotic lesions. Five groups of mice were studied; controls (C); mice fed a standard chow diet enriched with only cholic acid (CH); mice fed the high-cholesterol, high-fat Paigen diet (HF); mice treated with 0.5 g/kg P-407 every third day (P); and mice administered 0.5 g/kg P-407 every third day while consuming a diet identical to that of mice in group CH (PC). Neither a significant (p < 0.05) weight loss nor alteration in liver enzymes (AST and ALT) were observed for any group throughout the study when compared with the control mice. Total plasma cholesterol (CHOL) was significantly elevated compared with controls for mice in groups HF, P, and PC, whereas total plasma triglycerides (TG) were significantly increased for mice in only groups P and PC. Long-term ingestion of a high-fat diet or a diet enriched in cholic acid resulted in a significant (p < 0.05) reduction in HDL-CHOL when compared with controls. Plasma samples assayed at 200 days for mice in groups HF and P showed a shift in the lipoprotein fraction distribution primarily to VLDL-CHOL as compared with mice in group C in which, as expected, most of the CHOL was contained in the HDL fraction. The biologic activity of HMG-CoA reductase assayed in hepatic microsomal homogenates was significantly reduced for mice in groups CH (p < 0.01), HF (p < 0.01), and PC (p < 0.05), but not for mice in group P, when compared with control. A statistical analysis of the data demonstrated significant (p < 0.05) reductions in the HMG-CoA reductase mRNA levels in hepatic tissue for all treatment groups relative to mRNA levels determined for mice in group C. In contrast, no treatment group demonstrated a significant difference in hepatic LPL mRNA levels when compared with mRNA levels determined for control animals. These data demonstrate that P-407 administration to C57BL/6 mice significantly decreased the amount of HMG-CoA reductase mRNA detected in liver.
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PMID:Potential downregulation of HMG-CoA reductase after prolonged administration of P-407 in C57BL/6 mice. 1059 27

Solanum alatum Moench. has been shown to have a protective effect against carbon tetrachloride (CCl4)-induced liver injury. Solanum alatum treatment (100 mg/kg, p.o.) decreased the elevation of serum alanine aminotransferase (ALT; GPT) and aspartate aminotransferase (AST; GOT) induced by acetaminophen (paracetamol) (600 mg/kg, i.p.) administration. It also decreased the extent of visible necrosis in liver tissue. In addition, Solanum alatum treatment restored hepatic glutathione (GSH) depletion induced by acetaminophen (600 mg/kg, i.p.) administration. Microsomal enzyme levels such as P-450, reductase, and aniline hydroxylation enzyme were also restored to normal levels after Solanum alatum administration. The hepatoprotective mechanism may function through direct binding with acetaminophen toxic metabolites, decreasing the attraction of acetaminophen metabolites for other cellular GSH or thiol protein. Additionally, Solanum alatum treatment increased the concentration of hepatic GSH and maintained a high level activity of GSTase, which led to acceleration of the excretion of toxic acetaminophen metabolites.
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PMID:The hepatoprotective effects of Solanum alatum Moench. on acetaminophen-induced hepatotoxicity in mice. 1079 22

The purpose of this study is to evaluate the acute and chronic toxicology of oral intake of fish oil (omega-3 fatty acid) and garlic combination food supplements. These supplements were proven to have beneficial effects on the lipid profile. Therefore, it is important to evaluate the potential long-term effects of fish oil and garlic combination supplements on the biochemistry of organ structure and function. The hypothesis to be tested was that acute and chronic high-dose supplements of fish oil and garlic may not adversely affect organ histology but may influence certain metabolic activities. A double-blind, placebo-controlled study was carried out using 28 Sprague Dawley rats separated into a placebo group (16 rats) and a supplement group (12 rats). The supplement group received the ingredients in chow inserts at a dosage that was equivalent to three times the maximum safe daily dosage for fish oil and the usual daily dosage for garlic (the maximum safe daily dosage recommended by the United States Food And Drug Administration for a 70-kg human is a total of 3 g/day intake of EPA and HDA omega-3 fatty acids from conventional and dietary sources. The usual daily garlic usage is garlic powder = 1200 mg). The study was conducted over a period of 12 months with evaluations performed at baseline, 2 months, 6 months, and 12 months. Results confirm the expected acute triglyceride, total cholesterol and LDL suppression at these higher dosages in the supplement group. Acutely and chronically, there were no differences in external appearance, level of activity, daily food consumption, blood cell count, kidney function, thyroid function, prothrombin time (PT), and activated partial prothrombin time (PTT), which remained within normal ranges in the supplement group. Organ histology remained unchanged. Although during the chronic toxicity period the triglyceride and LDL suppression persisted, it was noted that total cholesterol and HDL levels increased. The increase in cholesterol and HDL in the supplement group during chronic toxicity periods is simultaneous with loss of suppression of plasma levels of other liver function marker enzymes, ALT and AST, which are not involved in cholesterol synthesis. This possibly suggests that other liver enzymes involved in cholesterol synthesis, such as HMG-co A reductase, follow a similar escape from suppression.
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PMID:Acute and chronic toxicity study of fish oil and garlic combination. 1172 96

In this study, PMC (2,2,5,7,8-pentamethyl-6-hydroxychromane), a derivative of alpha-tocopherol, dose-dependently (1-10 mg/kg) ameliorated the increase in plasma aspartate aminotransferase (GOT) and alanine aminotransferase (GPT) levels caused by chronic repeated carbon tetrachloride (CCl4) intoxication in mice. Moreover, PMC significantly improved the CCl4-induced increase of hepatic glutathione peroxidase, reductase, and superoxide dismutase activities. PMC also restored the decrement in the glutathione content of hepatic tissues in CCl4-intoxicated mice. Furthermore, it also dose-dependently inhibited the formation of lipid peroxidative products during carbon tetrachloride treatment. Histopathological changes of hepatic lesions induced by carbon tetrachloride were significantly improved by treatment with PMC in a dose-dependent manner. These results suggest that PMC exerts effective protection in chronic chemical-induced hepatic injury in vivo.
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PMID:The protective effects of PMC against chronic carbon tetrachloride-induced hepatotoxicity in vivo. 1172 62


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