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)

1. The metabolism of glutamine and alanine in the lung was studied in rats made septic by a caecal ligation and puncture technique. 2. The blood glucose concentration was not significantly different in septic rats, but blood pyruvate, lactate, glutamine and alanine concentrations were markedly increased as compared with sham-operated rats. Conversely, blood ketone body and plasma cholesterol concentrations were significantly decreased in septic rats. Both plasma insulin and plasma glucagon concentrations were markedly elevated in response to sepsis. Sepsis resulted in a negative nitrogen balance. 3. Sepsis increased the rates of production of glutamine (52.5%, P less than 0.001), alanine (38.9%, P less than 0.001) and glutamate (48.6%, P less than 0.001) by lung slices incubated in vitro. 4. Sepsis increased lung blood flow by 27.6% (P less than 0.05). Blood flow and arteriovenous concentration difference measurement across the lung of septic rats showed an increase in the net exchange rates of glutamine (142.5%, P less than 0.001), alanine (129.4%, P less than 0.001), glutamate (100.9%, P less than 0.001) and ammonia (138.0%, P less than 0.001) as compared with sham-operated control rats. 5. Sepsis produced significant decreases in the lung concentrations of glutamine (36.8%), glutamate (20.8%), 2-oxoglutarate (64.8%) and AMP (18.3%). The lung concentrations of alanine (95.9%), ammonia (67.7%) and pyruvate (89.7%) were increased. 6. The maximal activities of glutamine synthetase (20.4%, P less than 0.05), phosphate-dependent glutaminase (18.9%, P less than 0.05) and alanine aminotransferase (25.5%, P less than 0.05) were increased, but there was no marked change in that of glutamate dehydrogenase, in the lungs of septic rats.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Glutamine and alanine metabolism in lungs of septic rats. 168 36

The effect of ischemia on hepatic protein synthesis during sepsis is not known, but is of clinical relevance, since hepatic blood flow decreases during the late phase of sepsis. In this study, synthesis of acute-phase proteins was measured in perfused livers of rats 16 hours after sham operation or cecal ligation and puncture. Livers from each group had 45 minutes of complete ischemia or control perfusion. Protein synthesis was measured during two hour perfusion after the ischemia or control period, by determining incorporation of 3H-leucine into total secreted trichloracetic acid precipitated proteins, immunoprecipitated complement component C3 and albumin and phosphotungstenate-precipitated alpha 1-acid glycoprotein. Lactate, glutamine-oxalacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) levels in the perfusate were measured during preischemic and postischemic perfusion. Tissue glutathione levels were measured at the end of the perfusion. Synthesis of alpha 1-acid glycoprotein was increased by 100 per cent and albumin synthesis decreased by 46 per cent in septic livers, consistent with an acute-phase response and apparent downregulation of albumin synthesis during early sepsis. Synthesis rates were reduced by 50 to 60 per cent after ischemia in perfused livers from sham operated rats and 70 to 80 per cent in livers from septic rats. Hepatic production of interleukin-1 was not different between the groups during perfusion. GOT and GPT levels increased significantly during ischemia of both nonseptic and septic livers and rapidly returned toward baseline during reperfusion. Lactate levels were higher in perfusate of septic than of nonseptic livers before ischemia and increased further during ischemia. The results suggest that ischemia inhibits production of secreted hepatic proteins similarly in nonseptic and septic livers, but perhaps to a slightly greater extent in septic livers.
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PMID:Effect of ischemia on protein synthesis in the septic liver. 170 61

At sublethal concentrations, cypermethrin caused a decrease in total proteins and an increase in free amino acids, protease, alanine aminotransferase and aspartate aminotransferase in liver, brain and gill tissues of Tilapia mossambica. Nitrogen metabolic profiles like ammonia, urea and glutamine were also elevated in all the tissues as a consequence of cypermethrin toxicity. Glutamate dehydrogenase, AMP deaminase and adenosine deaminase activity was also increased in the present study.
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PMID:Cypermethrin induced changes in nitrogen metabolism of fish, Tilapia mossambica. 187 79

Protein is not normally an important energy fuel for exercising muscle. In spite of this, there is a significant increase in the rate of amino acid catabolism during exercise. This is secondary to the exercise-induced increase in several metabolic processes, such as hepatic gluconeogenesis and the citric acid cycle, where amino acid carbon is utilized. The suppression of protein synthesis during an exercise bout leaves amino acids available for catabolism. There is some evidence that basal amino acid concentrations in plasma and muscle may be higher in trained than in untrained individuals. In the rat, the concentration of free amino acids is higher in slow-twitch than in fast-twitch muscles. With short-term exercise, the transamination of glutamate by alanine aminotransferase leads to increased levels of alanine in muscle and plasma, and an increased release of alanine from the muscle. At the same time, the muscle and plasma glutamate concentrations are markedly decreased. The plasma glutamine level is elevated with short-term exercise, but changes in muscle glutamine concentration are more variable. With prolonged exercise, there is a depletion of the plasma amino acid pool, which may be explained by an increased consumption in organs other than muscle. With the exception of alanine, we found, however, that the muscle levels of free amino acids are kept stable throughout a 3.5-h exercise period. There is a significant activation of branched-chain amino acid metabolism with prolonged exercise, and the current data indicate that this is more pronounced in endurance-trained subjects than in untrained controls.
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PMID:Effect of exercise on amino acid concentrations in skeletal muscle and plasma. 196 May 12

In vivo studies with L-[13N]glutamate in the Walker 256 carcinosarcoma implanted under the renal capsule of female Sprague-Dawley rats demonstrate that uptake of glutamate and the rate of incorporation of the nitrogen label from this amino acid into metabolites is slower in the tumor than in nontumorous kidney tissue. Glutamate dehydrogenase, glutaminase, and alanine aminotransferase activities are significantly lower within the tumor than within the adjoining kidney. However, the tumor expresses high levels of aspartate aminotransferase, attesting to the importance of this enzyme in the metabolism of glutamate. Indeed, high performance liquid chromatographic analysis showed that the principal metabolic fate of label derived from L-[13N]glutamate in the tumor is incorporation into aspartate. Measurement of specific activity ratios of glutamate to aspartate shows that the transfer of nitrogen from glutamate to aspartate is rapid and that equilibration of label among components of the aspartate aminotransferase reaction is attained within minutes after tumor uptake. Analyses of the nontumorous portion of the implanted kidney also showed that aspartate is the major recipient of glutamate nitrogen. However, high performance liquid chromatographic analyses of deproteinized tissue revealed that glutamine and ammonia are also significant 13N-labeled metabolites formed from L-[13N]glutamate within the kidney. Proportionately lower amounts of these labeled metabolites were found in the tumor.
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PMID:Short-term metabolic fate of L-[13N]glutamate in the Walker 256 carcinosarcoma in vivo. 197 67

We evaluated glutamine synthetase (GS) and alanine aminotransferase (GPT) activities in biopsied muscle from 40 cases of various neuromuscular diseases. GS and GPT catalyze the synthesis of glutamine and alanine, respectively, from amino acids derived in part from the breakdown of muscle proteins. The subjects were 7 cases of muscular dystrophy; 1 Duchenne type (DMD), 3 limb-girdle type, 2 facioscapulohumeral type (FSH), 1 Fukuyama type (FCMD); and 1 myotonic dystrophy (MyD); 5 mitochondrial myopathies; 11 inflammatory myopathies including 6 polymyositis and 3 myopathy associated with collagen disease; 5 endocrinological myopathies including 2 periodic paralysis; and, 11 cases of neurogenic amyotrophies [4 amyotrophic lateral sclerosis (ALS), 4 spinal progressive muscular atrophy (SPMA) and 3 other types]. Control subjects were 8 patients with thigh operations. Biopsied muscle was homogenized and assayed for GS activity by the method of Smith et al.; GPT was assayed by commercial kit. Protein was assayed by the method of Lowry et al. Enzyme activities between mean -2SD and mean +2SD of controls were considered to be the normal range. GS activity in control subjects was 28.22 +/- 7.13 (mean +/- SD) nmol glutamine formed/mg protein/hr. Fifteen of 40 cases showed increased enzyme activity, including DMD and FCMD, the acute phase of polymyositis, and periodic paralysis. GPT activity in controls was 16.56 +/- 4.05 IU/mg protein. Sixteen of 40 patients showed increased enzyme activity: FCMD, FSH, MyD, inflammatory and endocrinological myopathy, and ALS. On the other hand, mitochondrial myopathy showed significantly decreased activity.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Studies on enzyme activities relating to amino acid mobilization in biopsied muscles]. 198 Jun 44

To contribute to our understanding of nitrogen metabolism in the developing chick we have studied in liver, intestine and yolk sac membrane the ontogeny of both aspartate- and alanine transaminases, glutamate dehydrogenase, adenylate deaminase, glutamine synthetase and xanthine dehydrogenase activities. Liver enzyme activities were much higher than those of the same enzymes in intestine and yolk sac membrane, the latter having the lowest activities. In the liver, both alanine transaminase and glutamate dehydrogenase increased their activity just before hatching, xanthine dehydrogenase and glutamine synthetase develop their highest activity just after hatching, while aspartate transaminase and adenylate deaminase attained the highest levels just with adulthood. From the pattern of enzyme activity in yolk sac membrane and intestine it can be inferred that after hatching, the amino-acid metabolism in these tissues is considerably enhanced, with higher production of ammonia from amino acids, as indicated by the rise in adenylate deaminase, as well as increased potentiality in production of both alanine and glutamine. It can be concluded that hatching coincides with a deep change of pace in amino-acid metabolism in the organs studied fully comparable with that observed in Mammals at the end of lactation, with the difference that the adaptation to the new diet in the case of the chick is much more sudden than weaning is for the rat.
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PMID:Amino-acid metabolism enzyme activities in the liver, intestine and yolk sac membrane of developing domestic fowl. 243 52

Models of hepatic intraacinar zonation have been proposed previously; in most models, direct visualization of the acinar destruction is not possible while intact hepatocyte recovery-viability often presents a problem for subsequent metabolic studies. In the present studies, the liver is isolated in situ and perfused with Krebs-Henseleit buffer, pH 7.4. A 1.5-mL intrahepatic volume of a 7 mM digitonin solution is then injected at a flow rate of 6 mL/min for 15 s via the portal vein or via the vena cava for selective destruction of the periportal (PP) or perivenous (PV) region of the acinus. To avoid diffusion of the detergent throughout the acinus, the liver is then immediately perfused with oxygenated Hanks buffer in the direction opposite to that of digitonin injection. The preparation can then be used for histological evaluation, for studies on isolated-perfused liver, or for isolation of hepatocytes. Direct visualization of the acinar destruction can be achieved by coloring the permeabilized cells with 0.2 mM trypan blue; the liver is then fixed in situ by a 10-min perfusion with paraformaldehyde and histological evaluation is achieved by eosine staining of liver slices. Following isolation of hepatocytes by collagenase perfusion, a highly significant PV localization was found for the synthesis of glutamine, the N-demethylation of aminopyrine, and the glucuronidation of p-nitrophenol, whereas a highly significant PP zonation was found for alanine aminotransferase. By contrast, no specific acinar zonation was found for the enzymes 7-ethoxycoumarin O-deethylase and aniline p-hydroxylase. Total cytochrome P-450 was 0.42 +/- 0.006 and 0.4 +/- 0.03 nmol/10(6) hepatocytes in PV and PP, respectively (nonsignificant).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Hepatic zonation of drug metabolizing enzymes. Studies on hepatocytes isolated from the periportal or perivenous region of the liver acinus. 251 8

Acute liver failure was induced in rats by a single intragastric dose of carbon tetrachloride. This causes hepatic centrilobular necrosis, as indicated by histological examinations, and produces a large increase in the activity of serum alanine aminotransferase. The plasma NH4+ level (mean +/- SEM) was 123 +/- 10 microM in the control group and 564 +/- 41 microM in animals with acute liver failure (each n = 5). 31P nuclear magnetic resonance (NMR) was used to monitor brain cortical high-energy phosphate compounds, Pi, and intracellular pH. 1H NMR spectroscopy was utilised to detect additional metabolites, including glutamate, glutamine, and lactate. The results show that the forebrain is capable of maintaining normal phosphorus energy metabolite ratios and intracellular pH despite the metabolic challenge by an elevated blood NH4+ level. There was a significant increase in the brain glutamine level and a concomitant decrease in the glutamate level during hyperammonaemia. The brain lactate level increased twofold in rats with acute liver failure. The results indicate that 1H NMR can be used to detect cerebral metabolic changes in this model of hyperammonaemia, and our observations are discussed in relation to compartmentation of NH4+ metabolism.
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PMID:Observation of cerebral metabolites in an animal model of acute liver failure in vivo: a 1H and 31P nuclear magnetic resonance study. 235 29

The effect of sterile inflammation and sepsis on the release of lactate and amino acids by peripheral tissues was investigated by removing the splanchnic organs (liver and small intestines) from the circulation and monitoring changes in plasma substrates for 30 min. Functional hepatectomy was performed in rats 5-7 days following the intraperitoneal introduction of a fecal-agar pellet (1.5 ml) [sterile vs. Bacteriodes fragilis (10(8) CFU) + E. coli (10(3) CFU)]. Following functional hepatectomy, dichloroacetate, an activator of the pyruvate dehydrogenase complex, significantly inhibited both lactate and alanine release. L-cycloserine, an inhibitor of alanine aminotransferase, significantly (P less than .05) reduced alanine following hepatectomy. Methionine sulfoximine, an inhibitor of glutamine synthetase, significantly (P less than .005) decreased glutamine accumulation following functional hepatectomy in each of the conditions examined. Treatment with each of these drugs abolished the differences between control and sepsis following hepatectomy. These results demonstrate that alterations in the amino acid profiles during sepsis may be modulated in peripheral organs pharmacologically by utilizing known inhibitors of critical regulatory enzymes.
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PMID:Pharmacologic modulation of increased release of gluconeogenic precursors from extra-splanchnic organs in sepsis. 257 28


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