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)

Oral administration of L-triiodothyronine (L-T3) (0.015-1 mg/kg) for 30 days to mature rats or cynomolgus monkeys resulted in both species in a high mortality at 1 mg/kg (after 2 weeks of treatment) and a progressive loss in body weight. Dose-related elevations in plasma marker enzymes occurred, mainly after 1-2 weeks of treatment. The approximate no-effect dose for these changes was around 0.015-0.020 mg/kg for both rat and primate. The large elevations of leucine aminopeptidase (LAP) at 1 mg/kg L-T3 in monkey indicated hepatocellular toxicity although in the rat such large increases in alanine aminotransferase (ALT) and glutamate dehydrogenase (GLDH) were not seen. L-T3 also showed little toxicity to rat hepatocytes in vitro. High concentrations of L-T3 (7 x 10(-9) to 7 x 10(-7) M) had minimal effects on parameters of cell viability such as lactate dehydrogenase (LDH) leakage, chromium-51 release and [3H]leucine incorporation. Urinary enzymes in the rat showed a similar profile to those in plasma. Large rises in alkaline phosphatase (AKP) and N-acetyl glucosaminidase (NAG) at 1 mg/kg indicated possible proximal tubular damage although this was not supported histologically. Clinically, in both species L-T3 appeared more toxic to males than females but this was not supported histologically. The histological lesions observed were different in the 2 species. In the monkeys there was extensive lipid vacuolation of hepatocytes and changes in thyroid and adrenal cortex. In the rat there was fine, non-lipid vacuolation of hepatocytes and thyroid changes. In the rat, 2 previously unreported lesions were also noted. There were multinucleated cells in the renal distal tubular epithelium, and focal fibroplasia of serosal surfaces of abdominal viscera.
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PMID:Comparison of the toxicity of orally administered L-triiodothyronine (T3) in rat and cynomolgus monkey. 320 78

The integrated use of several energy sources allows high muscular power outputs to be sustained. Muscle glycogen provides the major fuel source for muscular exercise, but other fuels can provide alternative energy sources which allow for muscle glycogen-sparing and an increased potential for prolonged high metabolic rates. Blood-borne glucose, derived from liver glycogenolysis and glyconeogenesis, as well as intra-muscular lipids and plasma free fatty acids derived from adipose tissue provide the main energy alternatives to muscle glycogen. Several amino acids, including the essential amino acid leucine, are also used directly as oxidizable fuels during exercise. Depending on the duration and intensity of exercise and other factors such as glycogen stores and energy intake, amino acids can provide from a few to approximately 10% of the total energy for sustained exercise. Additionally, many amino acids can be converted to glutamate (via glutamate dehydrogenase) and then to alanine (via glutamate-pyruvate transaminase). Alanine, along with lactate and pyruvate, are recognized as the major gluconeogenic precursors. Via this mechanism, several amino acids play crucial roles in providing the carbon sources for maintaining blood glucose homeostasis during exercise and glycogen restitution during recovery. And finally, during exercise and recovery, amino acids likely play important anaplerotic functions sustaining the whole metabolic apparatus.
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PMID:Amino acid and protein metabolism during exercise and recovery. 331 14

Hepatocytes from 12-day-old rats, pre and postnatally exposed to alcohol and pair-fed controls, were isolated and subfractionated in six cell subpopulations on Percoll density gradients. These cells were characterized using biochemical, stereological and cytofluorometric methods. Our results show that the low density cells (F2) are mainly perivenous cells, whereas the heavier cells (F6) were primarily periportal cells. These results were confirmed by alanine aminotransferase (ALAT), and glutamate dehydrogenase (GDH) activity levels and by stereological parameters. Alcohol seems to especially affect perivenous hepatocytes, with the damaged hepatocytes appearing in the perivenous and midzonal hepatocyte populations.
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PMID:Effect of pre- and postnatal exposure to alcohol on perivenous and periportal neonatal rat hepatocytes. 342 91

A model for immunologically T cell-mediated hepatitis was established in mice infected with lymphocytic choriomeningitis virus (LCMV). The severity of hepatitis was monitored histologically and by determination of changes in serum levels of the enzymes alanine aminotransferase (ALT), aspartate aminotransferase (AST), glutamate dehydrogenase (GLDH), and alkaline phosphatase (AP). Kinetics of histological disease manifestations, increases of liver enzyme levels in the serum, and cytotoxic T cell activities in livers and spleens all correlated and were dependent upon several parameters: LCMV-isolate; LCMV-WE caused extensive hepatitis, LCMV-Armstrong virtually none. Virus dose. Route of infection; i.v. or i.p. infection caused hepatitis, whereas infection into the footpad did not. The general genetic background of the murine host; of the strains tested, Swiss mice and A-strain mice were more susceptible than C57BL or CBA mice; BALB/c and DBA/2 mice were least susceptible. The degree of immunocompetence of the murine host; T cell deficient nu/nu mice never developed hepatitis, whereas nu/+ or +/+ mice always did. B cell-depleted anti-IgM-treated mice developed immune-mediated hepatitis comparably or even more extensively than control mice. Local cytotoxic T cell activity; mononuclear cells isolated from livers during the period of overt hepatitis were two to five times more active than equal numbers of spleen cells. Adoptive transfer of nylon wool-nonadherent anti-Thy-1.2 and anti-Lyt-2 plus C-sensitive, anti-L3T4 plus C-resistant lymphocytes into irradiated mice preinfected with LCMV-WE caused a rapid time- and dose-dependent linear increase of serum enzyme levels. This increase was caused by adoptive transfer of lymphocytes if immune cell donors and recipient mice shared class I, but not when they shared class II histocompatibility antigens. The donor cell dose-dependent increase of these enzymes was first measurable 6-18 h after transfer with 2 X 10(8) cells or 3 X 10(6) cells, respectively. The time-dependent increase caused by the adoptive transfer of 1-2 X 10(8) cells was strictly linear during a period of up to 25-40 h. These results indicate single-hit kinetics of liver cell death and suggest that effector T cells destroy infected liver cells via direct contact rather than via soluble toxic mediators. The results may represent the best in vivo correlate of the in vitro 51Cr-release assay that has been analyzed so far, and strongly support the view that antiviral cytotoxic T cells are directly cytolytic in vivo.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:T cell-mediated hepatitis in mice infected with lymphocytic choriomeningitis virus. Liver cell destruction by H-2 class I-restricted virus-specific cytotoxic T cells as a physiological correlate of the 51Cr-release assay? 348 5

Denervated dog gastrocnemius muscle has shown a progressive decrease in total protein content, alanine aminotransferase (AIAT), aspartate aminotransferase (AAT) and glutamate dehydrogenase (GDH) activity levels and elevation in free amino acid, ammonia, urea, glutamine contents and AMP deaminase activity levels during post-neurectemic days. The possible implications of these findings are discussed in relation to denervation atrophy.
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PMID:Skeletal muscle protein metabolism under denervation atrophy in dog, Canis domesticus. 357 Apr 36

Using fully mechanized analytical equipment, interference by haemolysis in the determination of 26 clinical chemical parameters was determined quantitatively by adding haemolysate to serum. Haemoglobin concentrations up to 6.6 g/l caused essentially no interference in the following determinations: albumin (immuno-nephelometric), alpha-amylase, calcium, chloride, cholesterol, cholinesterase, creatinine, iron, glucose, glutamate dehydrogenase, uric acid, urea, sodium, inorganic phosphate, total protein, transferrin and triglycerides. In the presence of haemoglobin, erroneously high values were found for: lactate dehydrogenase (haemoglobin higher than 0.2 g/l), aspartate aminotransferase, potassium and acid phosphate (haemoglobin higher than 1.5 g/l), creatine kinase (haemoglobin higher than 2.5 g/l) and alanine aminotransferase (haemoglobin higher than 3.4 g/l). Erroneously low values were found for bilirubin (haemoglobin higher than 0.8 g/l), alkaline phosphatase and albumin (by electrophoresis) (haemoglobin higher than 1.5 g/l) and gamma-glutamyltransferase (haemoglobin higher than 3.0 g/l).
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PMID:Haemolysis as an interference factor in clinical chemistry. 371 97

We produced three batches of a human-serum-based enzyme reference material (ERM) enriched with human aspartate aminotransferase (EC 2.6.1.1), alanine aminotransferase (EC 2.6.1.2), creatine kinase (EC 2.7.3.2), and lactate dehydrogenase (EC 1.1.1.27). The added enzymes were not exhaustively purified; thus the final ERMs contained some enzymes as contaminants, of which only glutamate dehydrogenase activity might interfere. The stability during storage and after reconstitution was good. The commutability of the four enzymes in the three ERM batches was also good, except when German or Scandinavian methods for aminotransferases were involved. The temperature-conversion factors for the ERMs were equivalent to those for patients' sera. Reactivation after reconstitution was complete within 5 min and was independent of the temperature of the reconstitution fluid. We believe that these secondary ERMs will aid in the transfer of accuracy between well-defined reference methods and daily working methods so that clinical enzymology results will become more comparable from laboratory to laboratory.
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PMID:Production and certification of secondary enzyme reference materials (ERMs). Part 1: Preparation of the sera and some of their properties. 375 8

After 7 weeks on a vitamin E deficient diet plasma and liver content of vitamin E were reduced by 60-70%. This treatment, a two week chronic ethanol intake or their combination all caused a significantly higher level of liver glutathione as compared to untreated rats. The chronic ethanol treatment also increased the activity of both alcohol dehydrogenase and aldehyde dehydrogenase and this effect was potentiated by vitamin E deficiency. The activity of the mitochondrial enzyme glutamate dehydrogenase was reduced both by vitamin E deficiency and by ethanol treatment. The activity of the cytosolic alanine aminotransferase was, on the other hand, markedly elevated by vitamin E deficiency, but this effect was completely abolished by ethanol treatment. Several similarities between the effects of chronic ethanol intake and vitamin E deficiency indicates that a poor vitamin E status may potentiate some of the ethanol-induced derangements in the liver.
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PMID:Combined vitamin E deficiency and ethanol pretreatment: liver glutathione and enzyme changes. 378 47

Ethanol metabolism in rat hepatocytes isolated either from the periportal (pp) or the perivenous (pv) area by collagenase gradient perfusion was compared to reveal metabolic factors that could be associated with the development of perivenous alcoholic liver damage. Cells were also isolated from rats given ethanol (E) chronically by addition to the drinking fluid. One group (EM) received in addition the alcohol dehydrogenase inhibitor 4-methylpyrazole, which potentiated the ethanol treatment by causing sustained elevated diurnal blood ethanol levels. Fatty degeneration ensued in only one-third of the E rats but in all of the EM rats. The periportal/perivenous activity distributions of alanine aminotransferase (ALAT) and glutamate dehydrogenase (GLDH) were 2.2 and 0.75, respectively. Both ethanol treatments significantly decreased the ALAT and increased the GLDH activities, but did not change their pp/pv distributions. Ethanol treatment also increased ethanol and acetaldehyde oxidation, but to the same extent in pp and pv cells. The increase was more marked in cells from EM rats despite their more severe liver fatty degeneration. Ethanol incubation also increased the lactate/pyruvate ratio to the same extent in pp and pv cells both from control or ethanol-treated rats. Our results indicate that periportal and perivenous hepatocytes convert ethanol via acetaldehyde to acetate equally well and with similar effects even after chronic ethanol treatment. Consequently, preferential damage of the perivenous area after chronic ethanol intake is not caused by inherent or acquired differences in ethanol metabolism between perivenous and periportal hepatocytes. Rather, sinusoidal gradients only established in the intact liver may exaggerate the metabolic imbalance by ethanol in the perivenous area, thus explaining its greater vulnerability to damage by alcohol abuse.
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PMID:Comparison of ethanol metabolism in isolated periportal or perivenous hepatocytes: effects of chronic ethanol treatment. 390

Previous observations that valproic acid (VPA) causes hepatic damage prompted us to investigate the effect of large doses of the drug (0.6, 1.2 and 1.8 mmol/kg/day) on a number of liver enzymes located on different subcellular fractions. In mitochondria, glutamate dehydrogenase, aspartate aminotransferase and ornithine carbamoyltransferase were significantly increased (1.8 mmol/kg/day). In microsomes, gamma-glutamyltransferase activity increased significantly (1.8 mmol/kg) and cytochrome P-450 content decreased significantly (1.2 and 1.8 mmol/kg). In cytosol, both aspartate and alanine aminotransferase activities were increased at all dose levels. These results indicate that VPA induces dose-dependent changes in some liver enzyme activities.
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PMID:Effect of sodium valproate on subcellular fraction enzymes in rat liver. 393 26


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