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)

The structural changes accompanying digitonin-induced release of enzymes and metabolites from isolated hepatocytes have been studied by scanning and transmission electron microscopy. In the initial phase, characterized by total release of the cytosolic marker enzyme, lactate dehydrogenase, the plasma membrane was immediately damaged, rapidly followed by extensive damage to the endoplasmic reticulum. The shape of the cell, however, was maintained, and the mitochondria and nucleus remained tightly held together by the cytoskeleton. Mitochondria remained intact initially, whereas the cytosol became less electron dense and the nuclear chromatin was more dispersed. An intermediate phase was characterized by total release of adenylate kinase and most of the glucose-6-phosphatase, marker enzymes for the mitochondrial intermembrane space and the endoplasmic reticulum, respectively. The outer mitochondrial membrane was ruptured, but mitochondria maintained their normal matrix electron density. In the final phase, characterized by the beginning of citrate synthase release from the mitochondrial matrix space, the mitochondria became swollen, and only the nucleus, inner and outer mitochondrial membranes, and the cytoskeleton could be clearly distinguished. Although the plasma membrane could not be readily discerned in electron micrographs after the initial phase, the plasma membrane marker enzyme 5'-nucleotidase remained associated with digitonin-treated hepatocytes. Acetyl-CoA carboxylase was released much more slowly than lactate dehydrogenase, indicating some severe restriction on its release. The release of acetyl-CoA carboxylase closely paralleled the release of glucose-6-phosphatase. The controlled exposure of hepatocytes to digitonin, therefore, leads to the sequential release of soluble, compartmentalized cellular components and some membrane-bound components, but the mitochondrial membrane, cytoskeleton and the nucleoskeleton survive even long-term digitonin treatment.
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PMID:Structural changes of isolated hepatocytes during treatment with digitonin. 614 31

A recently developed method for the (quantitative) demonstration of glucose-6-phosphate dehydrogenase activity in individual cells with the use of a polyacrylamide carrier has been extended for other enzyme cytochemical techniques. Isolated hepatocytes have been incorporated in the matrix of a thin transparent polyacrylamide gel prior to incubation in a cytochemical medium. The techniques which have been applied are the synthetizing reaction technique for glycogen phosphorylase, the indigogenic method for nonspecific esterase, the metal salt method for glucose-6-phosphatase, the post-azo-coupling technique for acid phosphatase, and the tetrazolium salt technique for succinate and lactate dehydrogenase activities. In all cases a few major problems which occur in the cytochemistry on single cells seem to be solved. The morphology is very well preserved, the final reaction product seems to be precipitated at the expected site of enzyme activity and the coloured end-product is highly specific for the enzyme activity to be studied, as has been demonstrated well with control experiments. The conclusion is reached, therefore, that this relatively simple device can be used routinely for the optimalization of enzyme cytochemistry of single cells.
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PMID:Enzyme cytochemical staining of individual cells with the use of a polyacrylamide carrier. Studies on the synthetizing reaction technique, the indigogenic method, the metal salt method, the post-azo-coupling technique, and the tetrazolium salt technique. 619 80

The level of oxidative phosphorylation, activity of phosphofructokinase, fructose-1,6-diphosphate aldolase, ketose-1-phosphate aldolase, glucose-6-phosphatase and lactate dehydrogenase are determined in subcellular fractions in the kidney cortex layer of rabbits which have suffered from acute ischemia (for 15, 30, 60, 120 min). Ischemia inhibits the oxidative processes in mitochondria which is proportional to the duration of the effect. An increase in the activity of glycolytic chain enzymes in microsomes and soluble fraction for 15-30 min of ischemia evidences for a compensation of the energy losses at the expense of glycolysis with short periods of ischemia. Glycolysis is inhibited with a more prolonged effect. It is established that the anti-ischemic protection of the organ viability is to be conducted not only with allo- but also with auto-transplantation of the kidney in case of short acute ischemia.
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PMID:[Energy metabolism in subcellular fractions of normal and acute ischemic kidneys]. 629 Dec 11

Fractions enriched in plasma membranes have been obtained from peripheral nerves enriched 89% in quiescent Schwann cells. Fractions were prepared from the intrafascicular tissue of desheathed distal stumps of cat sciatic nerve 8-10 weeks after transection and suture in the upper thigh. Tissue enriched in Schwann cells was minced, homogenized, and centrifuged to remove nuclei and undispersed tissue. Centrifugation of the resulting supernatant produced a pellet that was osmotically shocked, layered over a discontinuous sucrose gradient, and recentrifuged. Fractions enriched in plasma membrane (PM) markers were pooled, osmotically shocked for 16 h, layered over a second discontinuous sucrose density gradient, and recentrifuged. Membrane fractions (0.6 M:0.85 M and 0.85 M:1.0 M interfaces) contained a homogeneous population of unilamellar vesicles free of myelin. The 0.85 M fraction was enriched in 5'-nucleotidase, 2',3'-cyclic nucleotide 3'-phosphohydrolase. and specific [3H]ouabain binding, 4.8-, 3.0-, and 5.7-fold over the crude homogenate, respectively. These fractions also demonstrated low enzyme activities for succinate dehydrogenase, lactate dehydrogenase, and glucose-6-phosphatase (9, 13, and 15% of control values, respectively). Protein yield of the PM fraction (0.85 M) was approximately 0.6 mg/g of denervated nerve. This preparation should be suitable to characterize the surface properties of Schwann cells free of neuronal regulation.
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PMID:Isolation and partial characterization of plasmalemma from quiescent Schwann cells in denervated cat sciatic nerve. 630 68

We describe protocols for the fractionation of isolated hepatocytes into eight sub-populations using centrifugal elutriation. The distribution of fluorescein isothiocyanate and acridine orange in hepatocytes prepared from livers pre-perfused with one of these dyes is described and used as an indicator of acinar zone derivation for each population. The cytochrome P-450 content and response to induction by 3-methylcholanthrene and phenobarbitone; the distribution of lactate dehydrogenase, glucose-6-phosphatase, pyruvate kinase and tyrosine aminotransferase activities in the sub-populations is also reported. A marked asymmetry of distribution in all these activities was observed. On the basis of putative zone derivations (based on data of fluorescent dye distribution) of eight factors studied, the distributions of six were consistent with the sub-populations being derived from different acinar zones. Two major discrepancies were noted however, the distribution of pyruvate kinase activity and the response of the sub-populations to phenobarbitone. We conclude from this study that while a metabolic heterogeneity was revealed in the sub-populations generated, further characterisation is required to determine whether acinar zone separation has occurred and if so to what extent.
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PMID:Characterisation of hepatocyte sub-populations generated by centrifugal elutriation. 641 67

A diploid epithelial cell line (termed WB-F344) was isolated from the liver of an adult male Fischer-344 rat and the phenotypic characteristics of the cells were studied. These cells measure approximately two-fifths the volume of freshly isolated hepatocytes. They are histochemically negative for glucose-6-phosphatase and weakly positive for gamma-glutamyl transpeptidase. They produce extensive intercellular reticulin fibers which stain immunocytochemically for fibronectin, and they synthesize both alpha-fetoprotein and albumin, but they do not accumulate glycogen particles. Ultrastructurally, they are polygonal cells with numerous intercellular desmosomes and nexus junctions, and they are partially surrounded by basement membrane-like material. Cytoplasmic organelles include few, but sometimes dilated profiles of rough endoplasmic reticulum, lysosomes, abundant free ribosomes, sparse smooth endoplasmic reticulum and Golgi membranes, microbodies, and small, pleomorphic mitochondria. They express A and C isozymes of aldolase, K isozyme of pyruvate kinase, LDH2 to LDH5 isozymes of lactate dehydrogenase, and 'fetal liver'-type alkaline phosphatase isozyme. When compared with the phenotypes of isolated and purified normal hepatocytes, biliary epithelial (ductular) cells and 'oval' cells isolated from livers treated with chemical carcinogens, the phenotypic properties of the liver epithelial cell line in culture most resemble those of the 'oval' cells.
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PMID:A diploid epithelial cell line from normal adult rat liver with phenotypic properties of 'oval' cells. 646 34

Intramuscular injections of the title drug in a dose of 5 mg/kg (5% of the LD50) during 10 days produced in the liver and blood serum of white rats a decrease in the activity of glucokinase, succinate dehydrogenase, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, glutathione reductase, ATPase and ceruloplasmin. The urea content in total phospholipids rose, whereas the content of triglycerides and hexosamine diminished. Ten and 20 days after the drug was discontinued the majority of these characteristics returned to normal. The activity of glucosophosphate isomerase, transketolase, glucose-6-phosphatase, fructose-1,6-diphosphatase and lactate dehydrogenase as well as the content of total cholesterol, free fatty acids, tyrosine, hydroxyproline, total protein, RNA and DNA remained unchanged.
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PMID:[Effect of decane-1,10-bis[acetoxy-(N, N)-dimethyl-(N)-(diphenylmethoxy-2-ethyl) ammonium] dichloride on metabolism in white rats]. 651 57

The present study deals with the comparative efficacy of Hetrazan, levamisole and tetramisole on the enzyme activities of adult Setaria cervi worms. The drugs were administered orally to white rats, intraperitoneally infected with the bovine filariid, Setaria cervi. Biochemical assays revealed the decreased activities of glucose-6-phosphatase, fructose-1,6-diphosphatase, lactate dehydrogenase and adenosine triphosphatase in the drug-treated worms. Hetrazan was relatively more effective than tetramisole and levamisole. A possible role of these enzymes in the energy supply and survival of the worm has been briefly discussed.
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PMID:Effect of anthelmintics on the enzyme activities of Setaria cervi (Nematoda: Filarioidea). 661 75

The activities of various enzymes involved in detoxication and carbohydrate metabolism in the liver and the gastrointestinal tract of germfree (GF) and conventional (CV) rats, 8 and 40 weeks' old, were measured in relationship to intestinal microflora and aging. In 8-week-old rats, the activities of nitroreductase (NR) and aniline hydroxylase (AH) in the liver, and of alkaline phosphatase (ALP), maltase and lactase in the duodenum were higher in GF than in CV rats, but the activities of arginosuccinate synthetase (ASS) and lactate dehydrogenase (LDH) in the liver were higher in CV than in GF rats. In 40-week-old rats, the activities of NR and glucose-6-phosphatase dehydrogenase (G-6-PDH) of the liver and ALP, maltase and lactase of the duodenum were higher in GF than in CV rats, but those of ASS, UDP-glucuronyl transferase (UDP-GT), AH, beta-glucuronidase, and LDH of the liver were higher in CV than in GF rats. Compared between 8- and 40-week-old rats the activities of NR, beta-glucuronidase, LDH, and acid phosphatase increased with aging in both GF and CV rats. The specific activities of ASS in CV and UDP-GT and AH in GF rats decreased with aging. The total activities of ASS and AH in GF rats also decreased with aging. The activities of ALP, maltase and lactase decreased with aging in both GF and CV rats. Thus, these data suggested that there are influences of indigenous intestinal microflora and aging on the activities of various enzymes in the liver and gastrointestinal tract.
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PMID:Intestinal microflora and aging: age-related change of enzymes in the liver and the small intestine of germ-free and conventional rats. 679 85

The effect of daily intraperitoneal administration of Mn2+(4 mg/kg) was investigated on the metabolism of carbohydrates and certain enzymes involved in the oxidation of glucose in the rat liver and blood at the intervals of 30, 60 and 90 days after exposure. Mn2+ had no effect on the contents of blood reducing sugars and proteins, however the levels of pyruvic and lactic acids were reduced at 60 and 90 days after the metal treatment. The contents of liver glycogen and proteins remained unaffected while pyruvic acid content was decreased in Mn2+ treated rat liver throughout the experimental period. The activities of glycogen phosphorylase and lactate dehydrogenase decreased while that of phosphoglucoisomerase and glucose-6-phosphatase increased in the post mitochondrial supernatant at 60 and 90 days of Mn2+ exposure. The levels of hexokinase decreased and FDP-aldolase and fructose-1, 6-diphosphatase increased throughout the experimental period. The magnitude of alteration was found to be greater with the increase in the duration of Mn2+ treatment. Several of the mitochondrial enzymes in the liver were inhibited in the manganese exposed rats which may be responsible to inhibit the rate of dehydrogenation of Kreb cycle's intermediates along with the linked respiratory chain and eventually oxidation in the rat liver.
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PMID:Effects of manganese on carbohydrate metabolism and mitochondrial enzymes in rats. 713 26


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