Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.3.9 (glucose-6-phosphatase)
 3,081 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

2-Deoxy-D-galactose, in a dose of 3 mmol/kg, was administered intraperitoneally twice daily to young rats for periods up to 12 weeks. This dosage schedule resulted in recurrent phosphate trapping predominantly in liver. UTP deficiency was excluded by simultaneous uridine injections. Phosphate trapping was caused by the rapid accumulation of 2-deoxy-D-galactose 1-phosphate and was most pronounced in liver but also demonstrated in small intestine, brain, spleen, and thymus. The marked, although transient, drop in the hepatic content of inorganic phosphate triggered the catabolism of adenine nucleotides and a loss of ATP. Other metabolic pathways affected by phosphate deficiency include glycogenolysis and glycolysis. Increasing with time, repeated doses of the galactose analog led to retardation and arrest of growth, hepatomegaly, and splenomegaly. The average relative liver and spleen weights were elevated 2.5- and 4.5-fold, respectively, after 12 weeks of treatment. Liver damage was indicated by hyperbilirubinaemia and a progressive rise in the activity in plasma of sorbitol dehydrogenase, alkaline phosphatase, and gamma-glutamyltransferase. Examination by light and electron microscopy showed increasing numbers of vacuoles, surrounded by a single membrane, in hepatocytes, sinusoidal endothelial cells, and Kupffer cells. Focal cytoplasmic degeneration in hepatocytes was occasionally indicated by formation of autophagic vacuoles and finger print lysosomes. Hepatocytes of 2-deoxy-D-galactose-treated rats showed a dissociation and fragmentation of the rough endoplasmic reticulum. Sinusoidal endothelial cells and Kupffer cells were markedly enlarged, the latter contained a PAS-positive but amylase resistant substance. Extrahepatic changes included an increased occurrence of vacuolated cells in thymus. Phosphate trapping and its metabolic consequences are common phenomena in the experimental injury induced b 2-deoxy-D-galactose and in some hereditary diseases such as uridylyltransferase deficiency galactosaemia, fructose intolerance and glucose-6-phosphatase deficiency.
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PMID:Consequences of recurrent phosphate trapping induced by repeated injections of 2-deoxy-D-galactose. Biochemical and morphological studies in rats. 4 10

Sonic disrupted mitoplasts from 3-methylcholanthrene (MCA) treated rats can catalyze the formation of benzo(a)pyrene (BaP) adducts with calf thymus DNA in the presence of an NADPH generating system. The mitoplasts used in this study contained less than 1% microsomal marker enzymes: rotenone insensitive NADPH cytochrome c reductase and glucose-6-phosphatase. The rates of BaP metabolism and DNA adduct formation per nanomole cytochrome P-450 were different for MCA induced mitochondrial and microsomal enzymes. The major B(a)P DNA adducts formed in incubations with lysed mitoplasts were derived from reaction of 9-OH-B(a)P-4,5 oxide with deoxyguanosine. The results suggest a potential role of mitochondrial monooxygenase activity in the covalent binding of B(a)P to mitochondrial DNA.
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PMID:Formation of benzo(alpha)pyrene metabolites and DNA adducts catalyzed by a rat liver mitochondrial monooxygenase system. 299 32

Activities of key enzymes of gluconeogenesis--phosphoenolpyruvate carboxykinase, fructose-1,6-diphosphatase, glucose-6-phosphatase as well as the content of glycogen were studied in liver tissue of thymectomized rats. Gluconeogenesis was inhibited in liver tissue of these rats. As thymus and adrenal cortex are firmly related, the inhibition of gluconeogenesis in liver tissue of thymectomized rats appears to occur due to a decrease in the glucocorticoid activating effect followed the inhibition of adrenal cortex functions and absence of thymus hormones directly responsible for carbohydrate metabolism.
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PMID:[Effect of thymectomy on activity of key enzymes of gluconeogenesis in the rat liver]. 303 99

Thymectomized rats have been studied with the aim to determine the activity of gluconeogenesis key enzymes (phosphoenol pyruvate carboxykinase, fructose-1.6-diphosphatase, glucose-6-phosphatase), the glycogen content in the liver, the corticosterone level in blood and electrolytes concentration in erythrocytes and blood plasma. The activity of glucose-6-phosphatase and the glycogen content in the liver as well as the corticosterone level in the rat blood are shown to diminish after thymectomy. Changes are found in the electrolytic composition of blood as well as in the activity of key enzyme of the pentose cycle in erythrocytes. The data obtained indicate that thymectomy in rats is followed by the pronounced biochemical shifts induced by the thymus hormone deficiency and disturbance of interrelations in the system of neuroendocrine regulation.
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PMID:[Activity of key enzymes of gluconeogenesis in the liver and corticosterone levels of the blood of thymectomized rats]. 362 25

A delayed wasting syndrome similar to that induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was observed in male Sprague-Dawley rats exposed to 3,3', 4,4'-tetrachloroazoxybenzene (TCAOB) and 3,3',4,4'-tetrachloroazobenzene (TCAB). After a slow growth period, all treatment animals (25 mg/kg, i.p., 2 doses per week) exhibited a starvation-like syndrome characterized by reduced food intake, dramatic loss of body weight and subsequent death. Although the growth of all major organs in the treatment animals was affected, the thymus appeared severely atrophied. The growth kinetics during the earlier phase were further analyzed using serially-killed rats receiving TCAOB. In addition, TCAOB was found to markedly depress the specific activity (mumol/min/g wet liver) of glucose-6-phosphatase, fructose-1,6-bisphosphatase, phosphoenolpyruvate carboxykinase, and pyruvate kinase in the liver. Significant changes in the levels of cytochrome P-450, glutamic-pyruvic transaminase and malic enzyme in the liver were also observed.
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PMID:Delayed wasting syndrome and alterations of liver gluconeogenic enzymes in rats exposed to the TCDD congener 3,3', 4,4'-tetrachloroazoxybenzene. 401 2

The glucose-6-phosphatase dehydrogenase (EC 1.1.1.49) reaction of mouse organs was studied as affected by PPi and its diphosphonate analogs. It is shown that in vitro and hydroxy-1-ethane-1,1-diphosphonic acid) inhibit the mentioned enzyme of the mouse spleen and liver. The effect of hydroxyl-1-ethane-1,1-diphosphonic acid was used as an example to show that inhibition of glucose-6-phosphate dehydrogeanse by diphosphonates belongs to the mixed type characterized by changes in the Km and Vmax values. For the spleen enzyme Km equals 0.064 mM, Vmax - 4.7 Mg of NADPH per 1 mg of protein-1. h-1. Administration of methylene diphosphonic acid causes an inhibition in vivo of the glucose-6-phosphatase dehydrogenate activity of the liver but not of the spleen and thymus. Basing on the isoenzymic composition of the enzyme for the mentioned organs, it is possible to suppose that the difference in the methylene diphosphonic acid effect in the liver and lymphoid organs may depend on the differences in its isoenzymic spectrum. The fact that in vivo methylene diphosphonic acid in a dose having an immuno-depressive action has no influence on the activity of glucose-6-phosphatase dehydrogenase in the lymphoid organs, may evidence for the absence of the indirect immunodepressive effect of diphosphonate by affecting this enzyme.
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PMID:[Effect of inorganic pyrophosphate and its diphosphonate analogs on glucose-6-phosphatase dehydrogenase activity of mouse organs]. 625 95

Dynamics of 5 marker enzymes activity from subcellular particles--succinate dehydrogenase, beta-glucosidase, arylsulphatases A and B, acid RNAase and glucose-6-phosphatase--were studied in liver, spleen, thymus and blood serum of rats after single intragastric administration of T-2 toxin at a dose of 3.8 mg/kg (LD50). The acute intoxication was accompanied by an early (within 1-3 hrs) and significant reduction of total proteins in the tissues studied. Distinct tissue- and organelle-tropic effects of T-2 toxin were found: the toxin induced a gradual decrease in activity of the enzymes studied in liver tissue, while selective activation of lysosomal hydrolases was observed in spleen and thymus tissues. The selective effect of T-2 toxin on spleen and thymus lysosomal hydrolases appear to be involved in the mechanism of action of the toxin.
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PMID:[Effect of T-2 toxin on the activity of organelle-specific enzymes of various rat organs]. 631 90

Subacute experiments were made to examine the effect of the grain contaminated with Fusarium sporotrichiella on the activity of organelle-specific enzymes of the liver, thymus, spleen, bone marrow and blood serum of rats (beta-N-acetylglucosaminidase, alpha-mannosidase, beta-galactosidase, arylsulfatases A and B, succinate dehydrogenase, glucose-6-phosphatase, alkaline phosphatase, ketoso-1-phosphate aldolase) and on the protein content. The feeding of the grain provoked an early appearance of the symptoms of intoxication and a change in the activity of organelle-specific enzymes manifesting in the activation of lysosomal hydrolases in the thymus, bone marrow and spleen and in a decrease in the blood serum activity of the most enzymes investigated.
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PMID:[Enzyme characteristics of food poisoning caused by grain contaminated with Fusarium sporotrichiella]. 642 31

The time-course of the ultrastructural changes and activities of 6 marker enzymes of subcellular particles (succinate dehydrogenase, beta-glucosidase, beta-N-acetylglucosaminidase, acid RNAse, glucose-6-phosphatase and 5'-nucleotidase) has been studied in the liver, spleen and thymus in rats administered T-2 toxin (mycotoxin produced by some Fusarium species). A pronounced difference in the effect of T-2 toxin on the organs has been found. In the liver, the toxin induced a destruction of rough endoplasmic reticulum membranes, reduced ribosome number and progressively decreased activities of most enzymes. In the spleen, early and significant ultrastructural disturbances of all the cell membrane components and simultaneous lysosomal activation were observed. The changes in the thymus were characterized by a fast development of cell hydratation, organelle swelling and necrosis of some thymocytes with parallel increase in repair processes, infiltration by phagocytes and a selective activation of lysosomal hydrolases in the end of experimental time (72 h.). The results obtained emphasize an importance of cellular and subcellular membrane alterations in the mechanism of T-2 toxin action.
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PMID:[Effect of T-2 toxin on organ ultrastructure and organelle-specific enzyme activity in rats]. 665 69

Hepatomas tend to have a decreased glucose-6-phosphatase activity. We have observed phenotypic stability for this change in Morris hepatomas transplanted in rats. To determine if this decrease is selective for translocase functions or the hydrolase activity associated with glucose-6-phosphatase, we have compared activities in liver and hepatomas with glucose-6-phosphate or mannose-6-phosphate as substrates and with intact or histone-disrupted microsomes. In five out of seven subcutaneously transplanted rat hepatoma lines, the microsomal mannose-6-phosphatase activity was lower than in preparations from liver of normal or tumor-bearing rats. With liver microsomes and with most hepatoma microsomes, preincubation with calf thymus histones caused a greater increase in mannose-6-phosphatase than in glucose-6-phosphatase activity. In studies with liver and hepatoma microsomes there were similar increases in mannose-6-phosphatase activity with total calf thymus histones and arginine-rich histones. A smaller increase was seen with lysine-rich histones. The effect of polylysine was similar to the action of lysine-rich histones. There was only a small effect with protamine at the same concentration (1 mg/ml). Rat liver or hepatoma H1 histones gave only about half the activation seen with core nucleosomal histones. Our data suggested that microsomes of rat hepatomas tend to have decreased translocase and hydrolase functions of glucose-6-phosphatase relative to activities in untransformed liver.
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PMID:Changes in the glucose-6-phosphatase complex in hepatomas. 839 4


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