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:3.1.3.9 (glucose-6-phosphatase)
3,081 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Daily phenobarbital (PB) injections, on 3-7 consecutive days, induce an intense proliferation of smooth endoplasmic reticulum (ER) associated with a decrease of the glucose-6-phosphatase activity. This situation first affects the centrolobular hepatocytes, enhancing the degree of liver lobule heterogeneity. This experimental model was used for isolation and further subfractionation of hepatocytes on Ficoll density gradients, as described in the preceding paper. Profiles of protein, DNA, RNA, glycogen, phosphorylase, and glucose-6-phosphatase were determined all along the gradient. Two liver cell populations were distinguished: (a) light hepatocytes (mean density 1.10) present the same morphological characteristics as centrolobular cells, i.e., an abundant smooth ER composed of tubular elements, numerous small mitochondria, and few glycogen particles; (b) heavy hepatocytes (mean density 1.14) are characterized by large and compact glycogen areas and prominent rough endoplasmic cisternae, as are the perilobular cells. After incubation in the Wachstein-Meisel medium, Centrolobular hepatocytes exhibit dispersed reaction sites of glucose-6-phosphatase activity, whereas perilobular cells present a continuous and intense reaction. Morphometric determinations were carried out for both cell populations. Centrolobular PB hepatocytes are considerably enlarged (mean diameter: 23.7 mum); perilobular hepatocytes have a significantly smaller mean diameter of 19.2 mum, which is close to the values of control liver cells.
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PMID:Isolation of centrolobular and perilobular hepatocytes after phenobarbital treatment. 16 29

Hepatic carbohydrate metabolism in genetically diabetic mice (db/db) and their normal littermates has been studied. In db/db mice, body water was below normal and declined with age. The liver of db/db mice was abnormally large in relation to the metabolic mass of the body at all ages studied. In db/db mice, hepatic glycogenolysis, glycogen synthesis, glycogen synthetase, and phosphorylase were markedly increased. Gluconeogenesis from alanine or lactate in perfused livers of db/db mice was greater than normal per 100 g body water. Activities of fructose-1, 6-biophosphatase, glucose-6-phosphatase, glucokinase + hexokinase, and pyruvate kinase were elevated in livers of db/db mice. Diabetic mouse livers perfused with lactate showed a markedly reduced concentration of P-enolpyruvate and clear "forward crossover" between fructose-1, 6-P2 and fructose-6-P. In vivo glucose clearance, measured with [3-3H]glucose, in db/db mice was 170% that of normal mice. Data presented indicate that in livers of db/db mice: 1) glucose production is elevated prior to hyperglycemia, 2) glycogen turns over more rapidly, and 3) glycolytic and gluconeogenic enzymes are elevated paradoxically. These abnormalities are discussed from the viewpoint of their etiology.
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PMID:Hepatic metabolism of genetically diabetic (db/db) mice. I. Carbohydrate metabolism. 17 48

The histochemical method was used for determining glycogen, phosphorylase, glycogensynthetase, and glucose-6-phosphatase in order to evaluate the effect of progesterone on different morphological forms of cancer of the endometrium in man. On the basis of histochemical analysis of changes in the carbohydrate metabolism in 29 cases of cancer before and after treatment with progesterone a conclusion is drawn that sensitivity of tumours of the endometrium to hormonotherapy only partially depends upon the degree of their morphological differentiation.
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PMID:[A histochemical study of the effect of progesterone on the carbohydrate metabolism enzymes of different morphologic forms of endometrial cancer]. 17 78

Liver glucose-6-phosphatase and lipase-esterase, liver and muscle glycogen phosphorylase, and brown fat lipase-esterase activity changes were studied during the postnatal development of rats born and growing up in temperatures of +5 and 20 degrees C. Liver glucose-6-phosphatase activity was highest at the age of 4 days in both environments. In the age groups 20-67 days glucose-6-phosphatase activity was higher in animals living in a cold environment than in those reared at room temperature. At birth, glycogen phosphorylase activity was high in the liver but very low in the muscle. No difference was found between the two temperatures. The lipase-esterase activity in the liver was very low at birth, rising to adult level by the age of 30 days, while in the brown fat the activity was already high at the time of birth and clearly higher in rats born in a cold environment than in those born at room temperature. At the time of birth the relative and absolute weight of brown fat were also clearly higher in rats born at +5 degrees C than in those born +20 degrees C.
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PMID:Effects of a cold environment on energy-related enzyme activities in the postnatal rat. 17 36

The plausibility of various hypotheses concerning the effects of glucow dynamic model of glucose metabolism in the liver. The model consisted of six compartments representing extracellular glucose, and intracellular glucose, glucose 6-phosphate, glucose 1-phosphate, uridine diphosphate glucose, obtained from literature reports, the model predicted values of intermediates which were close to those reported for the liver, sampled from fasting animals. The model predicts that glucose can generate significant glycogen deposition by engendering the inhibition of glucose-6-phosphatase, but not by mass action, glycogen synthase activation, or phosphorylase deactivation. The model predicts that, although insulin can inhibit glucose production by lowering phosphorylase and gluconeogenesis, only an insulin-mediated induction of glucokinase can account for insulin's action to potentiate the effect of glucose alone on glycogen synthesis.
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PMID:Simulation study of control of hepatic glycogen synthesis by glucose and insulin. 18 69

The aim of the present work was to study by means of histochemical and chemical methods the 7-day course of changes in carbohydrate metabolism in the liver of male rats induced by a single dose of isoprenaline of 50 mg/kg administered subcutaneously. A statistically significant reduction was seen both in the level of free glycogen and lactate within 24 hours. The decrease of pyruvate level was not so marked. At the same time, there was increased, and within the hepatic lobules also extended activity of enzymes catalyzing glycogenolysis, i.e. alpha-glucan phosphorylase and particularly the branching Q-enzyme, glucose-6-phosphatase and LDH, whereas the level of malate and activity of SDH, which are constituents of the Krebs cycle, were found to be reduced. Cytochrome oxidase activity was changed after 24 hr compared to the controls. The obtained results indicate that an extensive glycogenolysis occurs in the liver of rats in the 24 hr following s.c. administration of isoprenaline, the major part of liver glycogen being degraded through glucose-6-phosphate to blood glucose and its metabolism via the Krebs cycle reduced. The observed metabolic changes are of reversible character and tend to normalize over the 2nd and 3rd day following isoprenaline administration.
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PMID:Study of histochemical and biochemical changes in the liver of rats induced by high doses of isoprenaline. 20 78

Biochemical and clinical studies on a patient with hepatic glycogen storage disease are reported. The patient showed many of the clinical and biochemical features of type I glycogenosis (glucose-6-phosphatase deficiency), but had normal activities of the following enzymes in liver tissue: glucose-6-phosphatase (EC3.1.3.9); amylo-1,6-glucosidase (EC3.2.1.33); glycogen phosphorylase (EC2.4.1.1); fructose-1,6-diphosphatase (EC3.1.3.11). The urinary excretion of 2-oxoglutaric acid was greatly increased in this patient and in a case of enzymologically proven type I glycogenosis. Abnormal 2-oxoglutaric aciduria has not been previously reported in the glycogen storage diseases. The results are discussed in relation to the possible nature of the underlying biochemical defect in patients of this type.
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PMID:Studies on a patient with in vivo evidence of type I glycogenosis and normal enzyme activities in vitro. 20 52

Liver glucose-6-phosphatase and phosphoenolpyruvate carboxykinase activities were increased in the postmature rat fetus (23.5 day old) when compared to term rat fetus (21.5 day old). Postmaturity was without effect on liver phosphorylase activity. The three liver enzyme activities were also determined in normal 2 day old neonates. These results are correlated with the mobilisation of fetal liver glycogen occuring during postmaturity in the rat and are discussed in relation to the secretory pattern of the pancreatic hormones.
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PMID:Postmaturity in the rat: phosphorylase, glucose-6-phosphatase and phosphoenolpyruvate carboxykinase activities in the fetal liver. 20 99

In skeletal muscles of the tortoise E. orbicularis, studies have been made on the content of glycogen, lactic acid, on the activity of glucose-6-phosphatase and phosphorylase. Histochemical studies were made on the lipid content. Experiments were performed on fast and slow bundles from mm. iliofibularis, testo cervicalis and retractor capitis. For comparison, the same indices of carbohydrate metabolism were investigated in fast m. plantaris and slow m. soleus of rats. In rats, slow muscles exhibit aerobic metabolism, in fast muscles--anaerobic one. In tortoises, slow muscles exhibit intermediate type of metabolism. Fast muscles show an anaerobic type or metabolism which is less intensive than anaerobic metabolism in slow muscles. Significant differences in some of the indices of carbohydrate metabolism were found in muscles which perform different functions in the organism.
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PMID:[Several features of the metabolism of the fast and slow muscles of Emys orbicularis tortoises]. 21 13

An experiment was conducted with turkey hens to investigate the effect of substituting 30% of the carbohydrate calories with corn oil, 1,3-butanediol, or glycerol. Birds fed additional corn oil had the lowest liver glycogen concentration. Corn oil increased phosphorylase, a total phosphorylase, and glycogen synthetase I in comparison to the controls. Also, additional corn oil resulted in the highest specific activity of glucose-6-phosphatase. Dietary glycerol caused the highest concentration of liver glycogen. Glycerol increased glycogen synthetase I, but had little effect upon total activity in comparison to butanediol in the diet. Both butanediol and glycerol gave similar phosphorylase a activity, but butanediol increased total activity. The fat-fed and control-fed hens regulated hepatic glycogen concentration through phosphorylase, while glycerol and butanediol-fed hens regulated glycogen through glycogen synthetase. In vitro activation of glycogen synthetase I was deficient in hens fed additional corn oil, indicating a lack of glycogen synthetase phosphatase activity. The order of activation (glycerol greater than butanediol greater than control greater than corn oil) corresponds to the rank of glycogen concentrations
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PMID:Effect of dietary energy on hepatic glycogen metabolism in the turkey hen. 22 May 98


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