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 bloom forming cyanobacterium (blue-green alga) Nodularia spumigena produced a peptide hepatotoxin with an LD50 of 70 micrograms/kg i.p. in mice. The livers of lethally poisoned mice were haemorrhagic and enlarged, the weight doubling to about 10% of total body weight. Histologically there was centrilobular to midzonal disruption and lysis of hepatocytes resulting in haemorrhage and formation of blood lakes. Death occurred approximately 1 hr after i.p. injection. By 30 min significant increases had occurred in the plasma levels of lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase and glucose paralleling degeneration and necrosis of centrilobular hepatocytes. In vitro the toxin caused rapid dose-dependent deformation of freshly isolated rat hepatocytes, which was accompanied by the activation of phosphorylase a; 125 ng/ml of toxin being sufficient to cause these changes in 10(6) cells. This work demonstrates that, both in vivo and in vitro, Nodularia toxin shares many similarities in its action to the well characterized peptide toxins of another cyanobacterium, Microcystis aeruginosa.
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PMID:Toxicity of the cyanobacterium Nodularia spumigena Mertens. 312 24

To determine whether respiratory muscles undergo alterations in enzyme activities of energy metabolism as a result of increased mechanical activity, adult male Wistar rats were subjected to a prolonged endurance training program. Analysis off maximal enzyme activity patterns in the diaphragm following 15 weeks of extreme training (final running duration: 210 min per day, 27 m.min-1 at 15 degrees grade, indicated significant reductions in the marker enzymes of the citric acid cycle (citrate synthase), glycolysis (pyruvate kinase, PK; lactate dehydrogenase, LDH), ketone body utilization (3-keto acid: CoA transferase) and transamination (glutamate pyruvate transaminase, GPT). No changes were found for the enzymes of glycogenolysis (phosphorylase, PHOSPH), glycolysis (glyceraldehyde phosphate dehydrogenase, GAPDH), glucose phosphorylation (hexokinase, HK) and beta-oxidation (3-hydroxyacyl: CoA dehydrogenase, HAD) following training. In contrast, in the external intercostal muscle, increases in the range of 57-77% were noted for the enzymes CS and HAD, whereas in the internal intercostal muscles no training induced alteration was evident for these enzymes. For both the intercostal muscles, a consistent trend was noted towards a reduction in all of the glycolytic enzymes investigated, however, significantly lower values were recorded for only PK and LDH in the internal intercostals. GPT was increased in the internal intercostal muscles. These findings indicate that the response pattern observed in the enzyme activities studied following training are to some degree specific to the respiratory muscle investigated.
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PMID:Differential response of enzyme activities in rat diaphragm and intercostal muscles to exercise training. 337 43

Drugs and chemicals that cause irreversible damage to cells may do so by producing specific defects in calcium regulation. The present studies examined glycogen phosphorylase as an index for assessing in vivo changes leading to excessive calcium ion activity, a putative pathogen, during the course of acetaminophen-induced liver injury. Administration of 500 mg/kg acetaminophen per os to mice depleted hepatic glutathione to a nadir by 1 h. Covalent binding to hepatocellular macromolecules commenced at this time and then rose out of the non-injurious background range at 1.5 h, coincident with a sharp rise in phosphorylase a activity. Phosphorylase activation preceded the leakage of alanine aminotransferase into plasma by several hours but appeared only after glutathione was depleted in excess of 80%. During the first 3 h, phosphorylase a activity rose in direct proportion to the amount of acetaminophen covalent binding. Glutathione depletion alone was not responsible for phosphorylase activation because the glutathione biosynthesis inhibitor, D,L-buthionine sulfoximine, produced comparable glutathione depletion but failed to stimulate phosphorylase activity or produce cell injury. Because phosphorylase a activity is thought to mirror changes in Ca2+ activity in vivo, these results support the hypothesis that acetaminophen-induced hepatocellular injury is related to the impairment of Ca2+ regulation.
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PMID:Immediate rise in intracellular calcium and glycogen phosphorylase a activities upon acetaminophen covalent binding leading to hepatotoxicity in mice. 338 36

The effects of paracetamol overdose on glycogen metabolism in rat liver have been investigated and related to its cytotoxicity. Paracetamol was administered to male rats by gavaging after a 24-h fast and refeeding was not permitted. An early (9-12-h) increase in histochemically demonstrable glycogen phosphorylase alpha activity in perivenous hepatocytes preceded major loss of membrane integrity as assessed by serum glutamate-pyruvate transaminase (SGPT) activity and uptake of trypan blue during perfusion. These changes occurred only after a decrease in the concentration of reduced glutathione, which is generally observed about 4 h after paracetamol treatment. The activation of glycogen phosphorylase in perivenous hepatocytes occurred concurrently with an increase in glycogen content of periportal hepatocytes, indicating a clear heterogeneity in the response of the two-cell populations to the hepatotoxin. The use of trypan blue perfusion together with histochemical techniques allowed changes in glycogen content and phosphorylase alpha activity of individual hepatocytes to be assessed with reference to the extent of membrane damage evident. The relevance of the results to possible mechanisms of hepatotoxicity is discussed.
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PMID:Histochemical and biochemical observations on the cytotoxicity of paracetamol and its effects on glycogen metabolism in rat liver. 342 88

The study of patterns of serum AST, ALT, CPK, LDH, and glycogen phosphorylase (GP) activity following bicycle ergometry in 26 male patients 1 to 1.5 months after myocardial infarction demonstrated no increase in AST, ALT and CPK activity, whereas total LDH activity was increased, with a tendency to elevated LDH-1 and LDH-2 fractions, as compared to the baseline, in those cases where exercise was discontinued because of ST depression. Patients with favorable response to bicycle ergometry that continued until the submaximum heart rate for a given age was achieved showed a tendency to elevated LDH-5 that may be a physiological response to exercise. The demonstrated increase in total GP activity, both in patients with exercise-induced ST depression and in those with elevated ST from the leads corresponding to the site of myocardial infarction, may reflect stress-induced reversible ischemia.
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PMID:[Effect of physical loading on serum enzyme activity in post-myocardial infarct patients]. 370 99

Postpubertal gilts averaging 111 kg and gaining 2.7 kg/wk were fed daily 1.9 kg/d of a diet providing 0.45, 2.1 or 83 mg of vitamin B-6/d. An additional group of animals were fed the high vitamin B-6 diet providing 83 mg of vitamin B-6/d for the initial 57 d of the experiment and then switched to 0.45 mg of vitamin B-6/d for the remainder of the 121-d experiment (61 gilts total). On d 0, 57 and 121, animals from each treatment were killed, and samples of the semitendinosus (ST) and semimembranosus (SM) were removed. Glutamic-oxaloacetic transaminase (GOT), glutamic-pyruvic transaminase (GPT), glycogen phosphorylase and pyridoxal phosphate (PLP) were measured in muscle tissues. The erythrocyte GOT activity coefficient indicated that gilts consuming 0.45 or 2.1 mg of vitamin B-6/d developed a vitamin B-6 deficiency. A vitamin B-6 deficiency resulted in the loss of whole-muscle transaminase activity (enzyme activity X muscle weight) with little effect on whole-muscle total phosphorylase or total PLP content. Excess dietary vitamin B-6 increased whole-muscle total PLP and total phosphorylase content with small decreases in whole-muscle transaminase. Under these conditions, muscle tissue acts as a nonmobile reservoir of PLP. Sixty to 95% of muscle PLP was bound to muscle glycogen phosphorylase.
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PMID:Effect of deficient and excess dietary vitamin B-6 on amino transaminase and glycogen phosphorylase activity and pyridoxal phosphate content in two muscles from postpubertal gilts. 403 60

1. The activities of gluconeogenic and glycolytic enzymes and the concentrations of citrate, ammonia, amino acids, glycogen, glucose 6-phosphate, acetyl-CoA, lactate and pyruvate were measured in kidney cortex of normal, diabetic, cortisone-treated and growth hormone-treated rats. 2. In kidney cortex of diabetic, cortisone-treated and growth hormone-treated rats the activities of glucose 6-phosphatase (EC 3.1.3.9), fructose 1,6-diphosphatase (EC 3.1.3.11) and phosphopyruvate carboxylase (EC 4.1.1.32) were increased. 3. The activities of glutamate dehydrogenase (EC 1.4.1.3), alanine aminotransferase (EC 2.6.1.2), aspartate aminotransferase (EC 2.6.1.10) and pyruvate carboxylase (EC 6.4.1.1) were increased in diabetic and cortisone-treated rats. In growth hormone-treated rats the activity of aspartate aminotransferase was depressed but those of the other three enzymes were unchanged. 4. The activity of hexokinase (EC 2.7.1.1) was not altered in any of these conditions. Phosphofructokinase (EC 2.7.1.11) activity was depressed only in growth hormone-treated rats. Pyruvate kinase (EC 2.7.1.40) activity was depressed in cortisone-treated and growth hormone-treated rats but unchanged in diabetic rats. 5. Amino acids, acetyl-CoA and glucose 6-phosphate contents were increased in rat kidneys in all these three conditions. Ammonia content was increased in diabetic and cortisone-treated rats but was markedly diminished in growth hormone-treated rats. 6. The [lactate]/[pyruvate] ratio was elevated in diabetic and cortisone-treated rats but unchanged in growth hormone-treated rats. Citrate content was increased in the kidney cortex of diabetic and growth hormone-treated rats but was unchanged in cortisone-treated rats. The activity of ATP citrate lyase (EC 4.1.3.8) was depressed in diabetic and growth hormone-treated rats but was increased in cortisone-treated rats. 7. Glycogen content was moderately elevated in growth hormone-treated rats and markedly elevated in diabetic rats, whereas no change in glycogen content was observed in cortisone-treated rats. Glycogen synthetase (EC 2.4.1.11) activity was unchanged in all these three conditions. Phosphorylase (EC 2.4.1.1) activity was not affected in cortisone-treated rats but was depressed in diabetic and growth hormone-treated rats.
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PMID:Evaluation of the rate-limiting steps in the pathway of glucose metabolism in kidney cortex of normal, diabetic, cortisone-treated and growth hormone-treated rats. 434 56

This paper demonstrates that the activities of glycogen phosphorylase (GP), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) are reduced in adult worms of the filarial nematode Litomosoides carinii recovered from pyridoxine-deficient cotton rats when compared to worms recovered from pyridoxine-sufficient controls. GP, ALT and AST activities were determined in adult worms L. carinii recovered from cotton rat hosts over a 20-week experimental period. Activities of GP, ALT and AST in the parasite showed a direct correlation with the dietary pyridoxine intake of their host. Throughout the experiment, enzyme activities were significantly lower (P < 0.001) in worms from rats fed a pyridoxine-free diet ad libitum that in worms from rats fed either a stock colony diet, a pyridoxine-free diet ad libitum with daily supplementation of 100 micrograms pyridoxine or limited amounts of pyridoxine-free diet with daily supplementation of 100 micrograms pyridoxine. The lower than normal activity of GP, ALT, AST and other enzymes dependent on the biologically active derivative of pyridoxine, the coenzyme pyridoxal-5-phosphate (PLP), interferes with the protein, carbohydrate and lipid metabolism of L. carinii and may in part cause the reduced establishment, development and growth of the parasite in pyridoxine-deficient hosts.
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PMID:Activities of glycogen phosphorylase, alanine aminotransferase and aspartate aminotransferase in adult worms of Litomosoides carinii recovered from pyridoxine deficient cotton rats (Sigmodon hispidus). 885 63

The activities of 18 enzymes involved in the intermediary and energy metabolism were measured in certain widely-spread peracarid crustaceans: 3 hypogean (Niphargus virei, Niphargus rhenorhodanensis and Stenasellus virei) and 2 epigean (Gammarus fossarum and Asellus aquaticus) ones. The activities of numerous enzymes were correlated with the known metabolic rates of the 5 species. Such rates are reduced in hypogean organisms: levels of enzymatic activity in subterranean species were 1.2 to 8.6 times lower than in epigean species for the main key regulatory enzymes involved in the Krebs cycle and glycolysis (phosphofructokinase, pyruvate kinase, hexokinase and citrate synthetase). The relative activities of phosphofructokinase, glycogen phosphorylase and hexokinase clearly indicated that glycogen was the main fuel oxidized in both epigean and hypogean organisms. A higher glycogen phosphorylase/hexokinase ratio in hypogean than in epigean crustaceans showed that subterranean species had a greater ability to function anaerobically. The presence of high activities of glutamate-pyruvate transaminase and lactate dehydrogenase in all species (and of malate dehydrogenase and fumarase in hypogean species) was indicative of a coupled fermentation of glycogen and glutamate during anaerobiosis, with lactate and alanine as end-products (as well as succinate in hypogean species). A low fructose-1,6-bisphosphatase/phosphofructokinase ratio, associated with a low level of phosphoenolpyruvate carboxykinase activity, indicated that the glycolytic pathway was active and that gluconeogenic ability was limited in epigean crustaceans. In contrast, in hypogean species, association of a higher ratio and a high level of phosphoenolpyruvate carboxykinase activity suggested a low glycolytic activity and a high gluconeogenic ability.
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PMID:The activities of enzymes associated with the intermediary and energy metabolism in hypogean and epigean crustaceans. 909 Nov 76

Preliminary short-term toxicity studies of sucrose acetate isobutyrate (SAIB) in the dog demonstrated that addition of this additive to the diet was associated with an increase in liver size and elevated serum alkaline phosphatase activity with no evidence of pathological change by light microscopy. To determine the basis for these changes, a 12-week oral toxicity study of SAIB was conducted in the dog and a similar study was performed in the rat. SAIB was fed in the diet to groups of six beagle dogs of each sex at 0, 0.5, 1.0, 2.0 and 4.0%. SAIB was also fed to groups of 40 Sprague-Dawley rats of each sex at levels of 0, 2.5, 5.0 and 10.0%. In the rat study, in addition to routine toxicology parameters, hepatic microsomal enzyme induction was determined using a zoxazolamine hypnotic test, urinary ascorbic acid excretion and determination of hepatic carboxylesterase activity. Sodium phenobarbital was fed to groups of 20 rats of each sex at a dose of 100 mg/kg body weight/day by gavage as a positive control for hepatic microsomal enzyme induction. In the dog study, routine toxicological tests were supplemented by tests for bromsulfophthalein (BSP) retention, histochemical staining of liver sections for glycogen, phosphorylase, succinate dehydrogenase, and acid and alkaline phosphatases. Levels of liver lipid, protein, glycogen and carboxylesterase activity were also determined. Electron microscopic examinations were made on liver sections from the dog study at the end of the 12-week SAIB feeding period and after a 2-week withdrawal period. Administration of SAIB to rats did not reveal evidence of any effect on hepatobiliary function, and there was no indication of microsomal enzyme induction. Body weight gain of male rats fed SAIB was decreased, probably as the result of decreased palatability of the diet; SAIB did not affect body weight gain in females. The changes observed in the dogs fed SAIB included increased serum alkaline phosphatase activity with no change in serum alanine aminotransferase, aspartate aminotransferase or lactic dehydrogenase activity and no change in serum electrolyte, serum protein, glucose or bilirubin levels. No haematological changes were observed. BSP retention was observed at all SAIB dose levels. There were no SAIB-related pathological changes in any organ when examined by light microscopy. Examination by electron microscope revealed dilatation of bile canaliculi and an increase in smooth endoplasmic reticulum compared with controls. Histochemical studies also indicated increased enzyme activity of the bile canaliculi. The electron-microscope-revealed changes were completely reversed during a 2-week treatment withdrawal period. The dog study did not establish a no-effect level for changes in hepatobiliary function induced by feeding SAIB.
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PMID:Subchronic toxicity studies of sucrose acetate isobutyrate (SAIB) in the rat and dog. 951 48


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