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)

Eight otherwise healthy insulin-dependent diabetic patients were subjected to controlled, symptomatic hypoglycaemia for 20 min (median glucose concentration 1.7 mmol/l, range 1.0-2.6 mmol/l). Concentrations of plasma adrenaline and plasma vasopressin were significantly increased, indicating normal counter-regulatory responses for these hormones. Plasma activities of the hepatic enzymes AST, ALT, LDH, GGT, and CK did not increase during or following the period of hypoglycaemia. Thus, abnormal plasma enzyme activities noted after clinical hypoglycaemia should be fully investigated, and not disregarded as due to the hypoglycaemic episode.
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PMID:A rise in the plasma activities of hepatic enzymes is not a common consequence of hypoglycaemia. 289 67

Ninety-four obese women were matched in pairs with similar body mass index and age but with as wide variations as possible in regional obesity, estimated by the waist/hip (W/H) circumference ratio. Body composition and metabolic variables were determined. The women were instructed to lower their energy intake to 1100 kcal/d, and were then seen every 4th week by a dietitian. After 5 per cent weight decrease initial measurements of body composition were repeated and when reaching weight steady state (less than 2 kg weight decrease upon two visits) both body composition and metabolic variables were again determined. Before the start of diet there was a positive correlation between W/H ratio on the one hand and insulin and alanine aminotransferase on the other. There was no correlation between rate of weight decrease, loss of cell body mass or diminution of circumferences with the W/H ratio. The examination of potential effects of dietary fibre on relapse is currently in progress.
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PMID:Dietary treatment of obesity localized in different regions. The effect of dietary fibre on relapse. 303 29

Leucine and monomethyl succinate initiate insulin release, and glutamine potentiates leucine-induced insulin release. Alanine enhances and malate inhibits leucine plus glutamine-induced insulin release. The insulinotropic effect of leucine is at least in part secondary to its ability to activate glutamate oxidation by glutamate dehydrogenase (Sener, A., Malaisse-Lagae, F., and Malaisse, W. J. (1981) Proc. Natl. Acad. Sci. U. S. A. 78, 5460-5464). The effect of these other amino acids or Krebs cycle intermediates on insulin release also correlates with their effects on glutamate dehydrogenase and their ability to regulate inhibition of this enzyme by alpha-ketoglutarate. For example, glutamine enhances insulin release and islet glutamate dehydrogenase activity only in the presence of leucine. This could be because leucine, especially in the presence of alpha-ketoglutarate, increases the Km of glutamate and converts alpha-ketoglutarate from a noncompetitive to a competitive inhibitor of glutamate. Thus, in the presence of leucine, this enzyme is more responsive to high levels of glutamate and less responsive to inhibition by alpha-ketoglutarate. Malate could decrease and alanine could increase insulin release because malate increases the generation of alpha-ketoglutarate in islet mitochondria via the combined malate dehydrogenase-aspartate aminotransferase reaction, and alanine could decrease the level of alpha-ketoglutarate via the alanine transaminase reaction. Monomethyl succinate alone is as stimulatory of insulin release as leucine alone, and glutamine enhances the action of both. Succinyl coenzyme A, leucine, and GTP are all bound in the same region on glutamate dehydrogenase, where GTP is a potent inhibitor and succinyl coenzyme A and leucine are comparable activators. Thus, the insulinotropic properties of monomethyl succinate could result from it increasing the level of succinyl coenzyme A and decreasing the level of GTP via the succinate thiokinase reaction.
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PMID:Regulation of insulin release by factors that also modify glutamate dehydrogenase. 304 28

To exclude the possibility that changes in hepatotoxicity and biotransformation were induced by diabetogen administration, the influence of long-lasting experimental insulin-dependent diabetes on the activities of benzphetamine demethylase, styrene oxide hydrolase, and UDP-glucuronosyl-transferases toward 1-naphthol, diethylstilbestrol, estrone and testosterone, and glutathione S-transferases toward 1-chloro-2,4-dinitrobenzene, ethacrynic acid, and sulfobromophthalein was studied. Adult male Sprague-Dawley rats injected with 45 mg streptozotocin/kg rapidly developed the classical symptoms of diabetes which persisted throughout the 90-day test period. Ketonemia was detectable at 6 but not at either 35 or 90 days after streptozotocin administration. After acute challenge with bromobenzene or carbon tetrachloride (CCl4), aspartate and alanine aminotransferase activities in rats diabetic for 35 and 90 days were markedly higher than those in normal rats, suggesting that diabetes potentiated the hepatotoxicity of these chemicals. Administration of 25 microliters CCl4/kg, ip, to diabetic rats decreased enzyme activities toward benzphetamine, sulfobromophthalein, 1-chloro-2,4-dinitrobenzene, and 1-naphthol. In normal rats, a dose of 400 microliters CCl4/kg, ip, was required to cause similar changes in enzyme activities. Bromobenzene (500 microliters/kg, ip) elicited opposing responses in diabetic and normal rats in N-demethylase activity, in UDP-glucuronosyltransferase activity toward 1-naphthol, estrone, and testosterone, and in glutathione S-transferase activity toward 1-chloro-2,4-dinitrobenzene. Total cytochrome P450 concentrations were reduced by both induction of diabetes and hepatotoxicant challenge. Thus, chronic uncontrolled diabetes alters the response of hepatic xenobiotic biotransformation enzymes in a non-uniform, substrate-dependent manner, independent of initial diabetogen effects. The role of cytochrome P450j in potentiating CCl4 toxicity is discussed.
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PMID:The effect of long-term streptozotocin-induced diabetes on the hepatotoxicity of bromobenzene and carbon tetrachloride and hepatic biotransformation in rats. 335 67

To estimate the number of adults medically eligible to donate blood, the percent of the general population over the age of 16 deferrable by 13 current American Red Cross donor guidelines was calculated using the best available United States data. Categories examined included age, weight, hematocrit, pregnancy, blood pressure, heart disease, diabetes requiring insulin, male homosexual activity since 1977, intravenous drug use, sexual partner of high-risk group member, recent transfusion, history of cancer, and other (medical, surgical, travel history). Sex-specific total eligibility rates were estimated by serial multiplication of individual eligibility rates (1.0 minus deferral rates) to account for the proportionate overlap of independent categories, with corrections for expected associations between categories. The resultant eligibility rates for women (57%) and men (70%) indicate fewer eligible donors than commonly stated. Surrogate testing (ALT, anti-HBc) for non-A, non-B hepatitis would further reduce the percent of eligible donors to 55 and 67%, respectively. Based on the actual numbers of women and men in the population, these calculations indicate that an equal number of women and men are medically eligible to donate.
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PMID:An estimate of blood donor eligibility in the general population. 337 67

(1) The acute effects of ethanol on protein synthesis by liver and skeletal muscle were investigated in young (95-100 g) rats. Rats were injected intraperitoneally with ethanol, 75 mmol/kg body wt; controls were injected with isovolumetric 0.15 M NaCl. After 140 min rates of protein synthesis were measured by injection of a large dose of L[4(3)H]phenylalanine and at 150 min rats were killed. (2) Fractional rates of protein synthesis in control animals were approximately four to five times greater in liver than muscle. Absolute rates were, however, comparable in liver and skeletal muscle. Ethanol reduced the fractional rate of liver protein synthesis by 5-20%; the response for muscle was relatively greater (25-30%). The decrease in the amount of protein synthesized by muscle was also greater than that by liver. (3) After 150 min, plasma gamma-glutamyl transferase, alanine aminotransferase, alkaline phosphatase, lactate dehydrogenase and creatine kinase activities were all decreased by 25-60%. Aspartate aminotransferase activity was increased by 42%, though this was not statistically significant. (4) Increased plasma glucose and triglycerides in ethanol-dosed rats indicated that limitations in substrate supply were not mediating factors in reducing protein synthesis. Ethanol was also able to exert its effects in the presence of elevated insulin levels. A direct effect of ethanol, or its metabolites, on protein synthesis, is therefore implied.
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PMID:Comparison of the acute effects of ethanol on liver and skeletal muscle protein synthesis in the rat. 339 Feb 39

Serum concentrations of total proteins, albumin, glucose, alkaline phosphatase, alanine transaminase, aspartate transaminase, gamma-glutamyltransferase, lactate dehydrogenase, creatine kinase, urea, creatinine, total calcium, ionised calcium, total magnesium, sodium chloride, potassium, phosphorus, cortisol, parathormone, 25-hydroxy-VitD3 and insulin as well as the results of haematological investigations in Cape vultures (n = 10) are presented.
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PMID:Serum biochemical and haematological parameters in the Cape vulture Gyps coprotheres. 350 9

Cirrhosis of the liver is characterized by glucose intolerance and hyperinsulinaemia. It is considered an insulin resistant state with both a receptor and a post-receptor defect of insulin activity. It would appear that reduced hepatic degradation rather than increased B-cell production is responsible for hyperinsulinaemia. The effect of surgical portosystemic shunt on insulin resistance was studied in 18 cirrhotics with impaired glucose tolerance (12 males, 6 females; mean age 46.9 +/- 0.7 years) by measuring: glucose production (3H-glucose infusion), glucose utilisation (euglycaemic clamp at approximately 100, approximately 1000 and approximately 10,000 microU/1), plasma insulin and C-peptide levels, and liver function indices (serum bilirubin, albumin, ALT, GGT) before and 2 months after surgery. Liver sorbitol clearance was also employed to measure variations in the functional liver plasma flow induced by the shunt. No significant changes were noted in: glucose production (1.94 +/- 0.17 SEM vs 1.96 +/- 0.17 mg/kg/min), glucose utilisation (metabolic clearance rate: 3.32 +/- 0.48 vs 3.42 +/- 0.43 at approximately microU/ml; 9.70 +/- 1.0 vs 9.16 +/- 0.9 at approximately 1000 microU/ml; 10.92 +/- 1.1 vs 11.07 +/- 0.8 ml/kg/min at approximately 10 000 microU/ml), fasting plasma insulin, C-peptide and C-peptide/insulin molar ratio (4.66 +/- 0.47 vs 5.50 +/- 0.54), and the liver function indices. By contrast, there was a significant decrease in functional liver plasma flow (813 +/- 34 vs 604 +/- 34 ml/min, P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Insulin resistance in human liver cirrhosis is not modified by porto-systemic surgical shunt. 352 84

Studies with brain alanine aminotransferase showed higher activity of the enzyme in the soluble fraction of cerebellum. Among the tissues, the liver soluble fraction was the richest source of the enzyme. Alloxan-induced diabetes caused both regional and time-dependent variations in the activity of brain alanine aminotransferase. Significant among these changes were the decrease in both soluble and particulate enzyme from cerebral hemispheres and an increase in the soluble enzyme activity from cerebellum at early stages of diabetes. Brain stem did not show any marked change in enzyme activity. Liver and heart enzyme, however, increased significantly after 1-2 weeks of diabetes. Insulin treatment to diabetic animals caused an 'over-shoot' in soluble alanine aminotransferase activity, particularly in cerebellum and liver.
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PMID:Influence of alloxan diabetes and insulin treatment on the activity of alanine aminotransferase in rat brain regions, liver and heart. 391 Apr 25

1. A method is described for extracting separately mitochondrial and extramitochondrial enzymes from fat-cells prepared by collagenase digestion from rat epididymal fat-pads. The following distribution of enzymes has been observed (with the total activities of the enzymes as units/mg of fat-cell DNA at 25 degrees C given in parenthesis). Exclusively mitochondrial enzymes: glutamate dehydrogenase (1.8), NAD-isocitrate dehydrogenase (0.5), citrate synthase (5.2), pyruvate carboxylase (3.0); exclusively extramitochondrial enzymes: glucose 6-phosphate dehydrogenase (5.8), 6-phosphogluconate dehydrogenase (5.2), NADP-malate dehydrogenase (11.0), ATP-citrate lyase (5.1); enzymes present in both mitochondrial and extramitochondrial compartments: NADP-isocitrate dehydrogenase (3.7), NAD-malate dehydrogenase (330), aconitate hydratase (1.1), carnitine acetyltransferase (0.4), acetyl-CoA synthetase (1.0), aspartate aminotransferase (1.7), alanine aminotransferase (6.1). The mean DNA content of eight preparations of fat-cells was 109mug/g dry weight of cells. 2. Mitochondria showing respiratory control ratios of 3-6 with pyruvate, about 3 with succinate and P/O ratios of approaching 3 and 2 respectively have been isolated from fat-cells. From studies of rates of oxygen uptake and of swelling in iso-osmotic solutions of ammonium salts, it is concluded that fat-cell mitochondria are permeable to the monocarboxylic acids, pyruvate and acetate; that in the presence of phosphate they are permeable to malate and succinate and to a lesser extent oxaloacetate but not fumarate; and that in the presence of both malate and phosphate they are permeable to citrate, isocitrate and 2-oxoglutarate. In addition, isolated fat-cell mitochondria have been found to oxidize acetyl l-carnitine and, slowly, l-glycerol 3-phosphate. 3. It is concluded that the major means of transport of acetyl units into the cytoplasm for fatty acid synthesis is as citrate. Extensive transport as glutamate, 2-oxoglutarate and isocitrate, as acetate and as acetyl l-carnitine appears to be ruled out by the low activities of mitochondrial aconitate hydratase, mitochondrial acetyl-CoA hydrolyase and carnitine acetyltransferase respectively. Pathways whereby oxaloacetate generated in the cytoplasm during fatty acid synthesis by ATP-citrate lyase may be returned to mitochondria for further citrate synthesis are discussed. 4. It is also concluded that fat-cells contain pathways that will allow the excess of reducing power formed in the cytoplasm when adipose tissue is incubated in glucose and insulin to be transferred to mitochondria as l-glycerol 3-phosphate or malate. When adipose tissue is incubated in pyruvate alone, reducing power for fatty acid, l-glycerol 3-phosphate and lactate formation may be transferred to the cytoplasm as citrate and malate.
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PMID:The intracellular localization of enzymes in white-adipose-tissue fat-cells and permeability properties of fat-cell mitochondria. Transfer of acetyl units and reducing power between mitochondria and cytoplasm. 439 82


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