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 effects of vitamin K3 treatment on the pharmacokinetics and metabolism of (+)-propranolol and the consequences of hepatic injury associated with vitamin K3 treatment were examined in groups of male Sprague-Dawley rats. When vitamin K3 (20 mg/kg) in polyethylene glycol 300 (PEG 300) was coinfused with (+)-propranolol (2 mg/kg) into the pyloric vein (a tributary flowing directly into the hepatic portal vein), a significant decrease in the intrinsic clearance of total drug (CLint) from 94.1 +/- 50.1 to 32.9 +/- 11.5 ml/min/kg was observed (p less than 0.01 vs. vehicle control). However, a lower dose of vitamin K3 (2 mg/kg in PEG 300) had little effect on this parameter. Interestingly, the PEG 300 vehicle control group exhibited a significantly (p less than 0.05) higher CLint than that observed in a saline control group (94.1 +/- 50.1 vs. 45.9 +/- 13.7 ml/min/kg). This difference appeared to be due to an increase in the free fraction of propranolol caused by PEG 300, because in vitro addition of this solvent to serum (at estimated in vivo concentrations) with or without added vitamin K3 doubled propranolol free fraction. Furthermore, rats that received the high dose vitamin K3 (20 mg/kg) treatment exhibited a pronounced increase in the serum concentration of enzymes of hepatic origin (alanine aminotransferase and sorbitol dehydrogenase) and in the incidence of hepatic necrosis. It was also observed that high-dose vitamin K3 treatment caused only minor changes in the urinary recovery of propranolol metabolites.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The influence of vitamin K3 treatment on the pharmacokinetics and metabolism of (+)-propranolol in the rat. 135 23

1. Aflatoxin B1 (1.5 mg/kg body weight, i.p.) was administered to rats, mice, quail and chickens to examine the comparative effect on hepatic microsomal drug-metabolizing enzymes, cytosolic glutathione S-transferase and serum enzymes. 2. Administration of aflatoxin B1 to rats resulted in a significant decrease in microsomal cytochrome P-450, NADPH-cytochrome c reductase, activities of aminopyrine N-demethylase, aniline hydroxylase, cytosolic glutathione S-transferase and liver glutathione content. However, no significant changes in these parameters were seen in mice. 3. Quail showed a significant decrease in the content of cytochrome P-450 and the activities of aminopyrine N-demethylase, aniline hydroxylase and cytosolic glutathione S-transferase. A similar treatment did not affect these biotransformation enzymes in chickens. 4. The activities of serum enzymes, sorbitol dehydrogenase, alanine aminotransferase and aspartate aminotransferase were increased significantly in rats and quail. Mice exhibited a significant increase in the activities of sorbitol dehydrogenase and aspartate aminotransferase, while chickens showed a significant increase only in alanine aminotransferase.
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PMID:Comparative assessment of the effect of aflatoxin B1 on hepatic dysfunction in some mammalian and avian species. 135 19

Fulvotomentosides (Ful) is the total saponins of Lonicera fulvotomentosa. In the present study, we examined the effect of Ful on acetaminophen (AA)-induced hepatotoxicity in mice. Ful pretreatment (75-225 mg.kg-1, sc x 3 d) significantly decreased AA (500 mg.kg-1, ip)-induced liver damage as indicated by serum activities of alanine aminotransferase and sorbitol dehydrogenase. Ful pretreatment (225 mg.kg-1, sc x 3 d) decreased hepatic cytochrome P-450, cytochrome b5, and NADPH-cytochrome c reductase by approximately 15-20%. Microsomes from Ful-pretreated mice, incubated in vitro with AA, produced less AA-glutathione. A 28% increase in urinary excretion of AA-glucuronide was observed in Ful (150 mg.kg-1, sc x 3 d) pretreated mice. Ful pretreatment had no influence on liver UDP-glucuronic acid concentration, but increased hepatic glucuronyltransferase activity towards AA. In summary, Ful pretreatment protects against AA-induced hepatotoxicity. One of the mechanisms for this protection appears to be the decreased AA toxic activation via P-450, as well as increased detoxication via glucuronidation of AA.
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PMID:Protective effects of fulvotomentosides on acetaminophen-induced hepatotoxicity. 144

Fulvotomentosides (Ful) is the total saponins of Lonicera fulvotomentosa. In the present study, we examined the effects of Ful on cadmium (CdCl2)-induced acute liver injury in mice. Ful pretreatment (150 mg.kg-1, sc x 3 d) remarkably decreased CdCl2 (3.7 mg Cd.kg-1, iv)-induced liver damage as indicated by serum activities of alanine aminotransferase and sorbitol dehydrogenase. Distribution of Cd to 12 organs and hepatic subcellular fractions was determined 2 h after Cd challenge. Ful pretreatment did not produce a marked shift in the distribution of Cd to various organs, but markedly altered the hepatic subcellular distribution of Cd, with more Cd bound to metallothionein (MT) in the cytosol, less in the nuclear, mitochondrial, and microsomal fractions. Ful pretreatment produced a dose-dependent increase in hepatic MT as determined by the Cd.hemoglobin assay. In conclusion, Ful protected against Cd hepatotoxicity by inducing MT, which binds Cd in the cytosol and lowers the amount of Cd available to other critical organelles and proteins.
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PMID:Protective effects of fulvotomentosides on cadmium-induced hepatotoxicity. 144 1

The purpose of this study was to determine the chronic toxicity of methidathion, an organophosphate insecticide, in dogs. Groups of beagle dogs, four/sex/dose, were fed methidathion at constant dietary concentrations of 0, 0.5, 2, 4, 40, or 140 ppm for 1 year. The equivalent daily dosages were approximately 0, 0.02, 0.07, 0.15, 1.4, and 4.7 mg/kg. There were no deaths or adverse clinical signs associated with the treatment. Weekly body weights and weight gains were not affected. Mean daily food consumption was reduced in male dogs given the 140-ppm diet. Major treatment-related effects were cholestasis, chronic inflammation in the liver, and cholinesterase (ChE) inhibition. The liver effects were indicated by gross and microscopic pathologic findings as well as moderate increases in serum bile acids and enzyme activities (alanine aminotransferase, aspartate aminotransferase, sorbitol dehydrogenase, and alkaline phosphatase) in all dogs receiving greater than or equal to 40 ppm. RBC ChE was inhibited in males at greater than or equal to 40 ppm and in females and 140 ppm. Brain ChE was inhibited in both sexes at 140 ppm; the magnitude of inhibition relative to control was slightly greater with the cerebellar fraction than with the cerebral fraction. Serum ChE was not affected at any dose level. In conclusion, liver was the target organ in beagle dogs given greater than or equal to 40 ppm (equivalent to 1.4 mg/kg/day) methidathion in diet for 1 year. The no-observable-effect level was 4 ppm (0.15 mg/kg/day) for both liver cholestasis and ChE inhibition.
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PMID:One-year dietary toxicity study with methidathion in beagle dogs. 151 89

Recently, we demonstrated that a microsomal enzyme inducer with a steroidal structure, pregnenolone-16 alpha-carbonitrile (PCN), markedly decreased the hepatotoxicity of acetaminophen (AA) in hamsters. Therefore, it was of interest to determine if PCN, as well as another steroid microsomal enzyme inducer, dexamethasone (DEX), would decrease the toxicity of AA in mice, another species sensitive to AA hepatotoxicity. Mice were pretreated with PCN or DEX (100 and 75 mg/kg, ip, for 4 days, respectively) and were given AA (300-500 mg/kg, ip). Twenty-four hours after AA administration, liver injury was assessed by measuring serum activities of sorbitol dehydrogenase and alanine aminotransferase and by histopathological examination. Neither PCN nor DEX protected markedly against AA hepatotoxicity in mice; PCN tended to decrease AA-induced hepatotoxicity, whereas DEX was found to enhance AA-induced hepatotoxicity and it produced some hepatotoxicity itself. DEX decreased the glutathione concentration (36%) in liver and increased the biliary excretion of AA-GSH, which reflects the activation of AA, whereas PCN produced neither effect. Thus, whereas PCN has been shown to markedly decrease the hepatotoxicity of AA in hamsters, apparently by decreasing the isoform of P450 responsible for activating AA to N-acetyl-p-benzoquinoneimine, this does not occur in mice after induction with either PCN or DEX. In contrast, DEX enhances AA hepatotoxicity apparently by decreasing liver GSH levels and increasing the activation of AA to a cytotoxic metabolite.
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PMID:Effect of pregnenolone-16 alpha-carbonitrile and dexamethasone on acetaminophen-induced hepatotoxicity in mice. 164 53

Chlordecone (CD) pretreatment is well known to greatly potentiate CCl4 toxicity. Previous work has shown that suppression of hepatocellular regeneration permits an ordinarily limited liver injury to progress in an irreversible manner. Insufficient hepatocellular energy has been proposed as a mechanism for suppressed hepatocellular regeneration. Since cyanidanol reportedly increases cellular ATP, this compound was employed to test the above hypothesis. The present study was designed to investigate the sequential biochemical and histological changes over a time course of 120 hr after CCl4 administration. Male Sprague-Dawley rats (125-150 g) were maintained on 10 ppm CD diet for 15 days and were challenged with either a standard protocol dose (100 microliters/kg) or a low (50 microliters/kg, L) dose of CCl4. Cyanidanol pretreatment at 48, 24, and 2 hr before CCl4 administration to rats maintained on CD diet resulted in 100 or 70% animal survival, for CCl4 (L) or the standard dose of CCl4, respectively. Preliminary studies indicated that neither simultaneous nor subsequent administration of cyanidanol with CCl4 challenge affords such protection. Prior treatment with cyanidanol and a latency period were found necessary for protection. Without cyanidanol, CD + CCl4 combination caused 50 and 100% lethality after CCl4 (L) and the standard dose, respectively, while the same doses of CCl4 alone did not cause lethal effects. Plasma enzymes (alanine aminotransferase, aspartate aminotransferase, sorbitol dehydrogenase) in control rats showed only moderate and transient increases after CCl4 challenge. The combination of CD + standard dose of CCl4 resulted in progressive and marked elevations of all three serum enzymes at all time intervals until the death of animals. Cyanidanol pretreatment resulted in significant decline in the plasma enzyme elevations at later time points. Cyanidanol pretreatment increased hepatic ATP synthesis in control or CD rats. CCl4 administration to control rats did not alter hepatic ATP levels, while in CD-fed rats hepatic ATP levels were significantly decreased. Cyanidanol pretreatment to CD + CCl4 combination-treated rats did not significantly prevent the decline in hepatic ATP and glycogen levels. However, in the surviving rats a recovery in these parameters was observed. Light microscopic examination of livers from animals that received CCl4 alone revealed only marginal cellular injury, at early time points only. However, CCl4 challenge to rats maintained on CD resulted in progressive injury, characterized by the appearance of ballooned cells, necrotic cells, and cells with lipid droplets in the liver. Cyanidanol pretreatment to these rats caused decreased vacuolation and significantly reduced the progression of liver necrosis.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Protection from chlordecone-amplified carbon tetrachloride toxicity by cyanidanol: biochemical and histological studies. 170 39

Pharmacokinetic modeling has been very useful in examining the complex relationships between exposure concentration and target tissue dose. This study utilizes a physiologically based pharmacokinetic (PB-PK) modeling approach for assessing the metabolism of BrCCl3 and to investigate its relationship with hepatotoxicity and lethality. Male Sprague-Dawley rats maintained for 15 days on normal diet (control), or on diets containing either chlordecone (CD, 10 ppm), phenobarbital (PB, 225 ppm) or mirex (M, 10 ppm), were used in gas uptake studies to determine the kinetic constants of BrCCl3 metabolism. Four initial concentrations of BrCCl3 at approximately 30, 200, 700, and 3000 ppm were used for each group. The uptake data were analyzed by computer simulation using a PB-PK model containing relevant tissue solubilities and physiological parameters as well as an equation describing the behavior of BrCCl3 in the closed chamber atmosphere. Liver injury was assessed by serum enzyme elevations (alanine aminotransferase, aspartate aminotransferase, and sorbitol dehydrogenase) and histopathological examination, at 24 hr after the exposure to BrCCl3. Another group of similarly pretreated rats was exposed to BrCCl3 and observed over a 14-day period for mortality. Dietary exposures resulted in increased Vmaxc value for BrCCl3 metabolism as compared to control (3.55 +/- 0.14 mg/hr/kg) for PB (8.52 +/- 0.28 mg/hr/kg) and M (5.06 +/- 0.19 mg/hr/kg) but not for CD (3.92 +/- 0.19 mg/hr/kg). Kfc, the first-order rate constant for BrCCl3 metabolism, was decreased after PB (12.9 +/- 0.5 hr-1/kg) and increased after M (17.6 +/- 0.5 hr-1/kg), but unchanged after CD (15.5 +/- 0.6 hr-1/kg) exposure as compared to control (15.0 +/- 0.3 hr-1/kg). The total amount of BrCCl3 metabolism at any initial concentration employed remained unchanged in all the pretreated groups as compared to control. However, the amount of BrCCl3 metabolized through saturable pathway only, at higher initial concentrations, was increased in the PB and M pretreated groups, but not in the CD pretreated group. It is concluded that the rates of metabolism of BrCCl3 were unchanged after CD pretreatment as compared to control, while PB and M pretreatment alter both the saturable and first-order rates. Serum enzymes were significantly increased in all the groups after exposure to BrCCl3 at 200 and 700 ppm concentrations. The increase was more pronounced in PB and M pretreated groups as compared to control and CD pretreated groups. Similarly, histopathological examination of liver showed alterations in the lobular architecture, the extent of alterations being dependent on the dose of BrCCl3 and the pretreatment.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:PB-PK derived metabolic constants, hepatotoxicity, and lethality of BrCCl3 in rats pretreated with chlordecone, phenobarbital, or mirex. 171 92

The hematologic and clinico-pathologic response to Fascioloides magna infection in cattle and guinea pigs was investigated. Twelve calves (six infected and six controls) were monitored for 26 weeks after inoculation with 1000 metacercariae. All calves remained healthy and there were no significant differences in weight gains between infected and control groups. Flukes (mean = 9.2, range 1-32) were recovered from the liver and abdominal cavity of all infected calves. The only significant response observed in the complete blood counts was an eosinophilia present in the infected calves extending from Weeks 2 to 26 post-infection. There were no significant differences in serum levels of aspartate aminotransferase and only minor increases in the levels of gamma-glutamyl transferase and sorbitol dehydrogenase. A total of 48 infected and 48 control guinea pigs from three separate experiments were monitored for 16 weeks after inoculation with 20 metacercariae of Fascioloides magna. Infected guinea pigs died between 7 and 114 days after infection, and flukes (mean = 2.5, range 0-13) were recovered from the liver, abdominal cavity, lungs, thoracic cavity, skeletal muscle and subcutaneous tissue. There were no differences in weight gains between infected and control guinea pigs. Complete blood counts showed increases in white blood cells, monocyte and neutrophil counts from between the third and fourteenth weeks post-infection; however, the differences were not consistently significant. Infected guinea pigs developed a significant eosinophilia and basophilia from 2 to 16 weeks post-infection. There were no significant changes in the serum levels of alanine aminotransferase or gamma-glutamyl transferase. There was an increase in the serum levels of aspartate aminotransferase beginning at 5 weeks post-infection. The response observed in the guinea pigs was similar to that reported in sheep, suggesting the suitability of the guinea pig as a model for Fascioloides magna infection in the sheep.
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PMID:Hematology and clinical pathology of experimental Fascioloides magna infection in cattle and guinea pigs. 178 31

Chloroform was administered ip to Balb/c mice as a single dose ranging from 1/8 to 1 of the approximate lethal dose. At different time periods after administration, mice were sacrificed. Serum glutamate-pyruvate transaminase (SGPT) and sorbitol dehydrogenase (SDH) as well as glutathione (GSH) and malondialdehyde (MDA) levels in the liver were determined. Increased SGPT and SDH levels were found for all doses exceeding 1/8 of the approximate lethal dose. The depletion of GSH level was kept within 40% for all doses. A 2-4 fold increase of hepatic MDA level was found. The depletion of hepatic GSH and, to some extent the increase of serum SGPT and SDH, occurred in biphasic fashion. Dose-effect functions for these biochemical alterations could only be constructed for the second, delayed phase of action. It is postulated that the hepatotoxicity of chloroform is mainly dependent on radical formation in the course of biotransformation.
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PMID:The hepatotoxic action of chloroform: short-time dynamics of biochemical alterations and dose-effect relationships. 181 48


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