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)

Electron microscopic cytochemistry was used to determine the localization of five phosphatase enzymes-glucose-6-phosphatase, inosine diphosphatase, thiamine pyrophosphatase, acid phosphatase, and adenosine triphosphatase-in control human testes. Glucose-6-phosphatase occurred in the endoplasmic reticulum and nuclear envelope of Sertoli cells, Leydig cells and primitive spermatogonia, but was not observed in more advanced spermatogenic cells. The presence of glucose-6-phosphatase activity paralleled the presence of glycogen in spermatogenic cells, i.e., both occurred in type AL and AD spermatogonia but not in type AP or B spermatogonia or in more advanced spermatogenic cells. Inosine diphosphatase activity was found in the endoplasmic reticulum, nuclear envelope, and Golgi complex of Sertoli cells and all spermatogenic cells except late spermatids. Additionally, inosine diphosphatase activity was localized at the junctions between Sertoli cells and late spermatids, but was not associated with any other plasma membrane. Thiamine pyrophosphatase reaction product was found in the Golgi bodies of Sertoli cells and in spermatogenic cells through immature spermatids. Neither inosine diphosphatase nor thiamine pyrophosphatase was observed in the Golgi bodies of spermatids during acrosomal formation. Acid phosphatase activity was found in lysosomes of spermatogonia, spermatocytes, and spermatids, in lysosomes of Leydig cells, and in lysosomes, lipofuscin bodies, and Golgi cisternae of Sertoli cells. It is thought that Sertoli lysosomes play a role in the phagocytosis of degenerating germ cells; however, the role of spermatogenic or Leydig lysosomes is unknown. Adenosine triphosphatase activity occurred at the interfaces between two spermatogonia, and between Sertoli cells and spermatogonia, but was not observed in the spaces between two Sertoli cells, two spermatocytes, two spermatids, or between Sertoli cells and spermatocytes, or between Sertoli cells and spermatids.
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PMID:The fine structural localization of testicular phosphatases in man: the control testis. 17 58

A rat liver nuclear envelope fraction isolated essentially by the technique of Monneron et al. (J. Cell Biol. 55, 104-125 (1972) is characterized by high levels of glucose-6-phosphatase and 5'-nucleotidase. A broadly specific nucleoside triphosphatase activity is present. Cytochromes b5 and P-450 as well as NADPH- and NADH-cytochrome c reductase activities are present but at lower levels than found in microsomes. Cytochrome c oxidase activity is low. RNA polymerase activity is absent from the nuclear envelope fraction. Cytochemistry shows that glucose-6-phosphatase activity is strong and restricted to the nuclear envelope of nuclei. 5'-Nucleotidase shows weak reaction deposit in whole nuclei but in contrast gives clear reaction deposit in isolated nuclear envelopes. Cytochemical reaction deposit due to nucleoside triphosphatase activity is not restricted to the nuclear envelope but is found to a larger extent within the nucleus.
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PMID:An enzymic analysis of a nuclear envelope fraction. 18 34

The experiment was carried out on rats, which were divided into three experimental and one control groups. The experimental animals were intraperitoneally injected with furfural in the dose of 58 mg/kg body weight for 30 days. In the liver samples obtained at autopsy, apart from routine staining with hematoxylin and eosin, estimation of the activity of the following enzymes was made: succinic dehydrogenase. NADH-tetrazol reductase, lactic dehydrogenase, glucose-6-phosphate, adenosine-triphosphatase, Ca-formol, glucose-6-phosphatase and acid phosphatase. Glycogen content was also evaluated. A temporary decrease in the activity of reactions for the enzymes of tissue respiration, an increase in the activity of glucose-6-phosphatase with a simultaneous decrease of glycogen content, activation of intracellular digestive processes, and inhibition of active transport through biological membranes were found in animals intoxicated with furfural.
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PMID:[Morphological and histochemical changes in the rat liver in chronic furfural poisoning]. 20 22

In a stop-experiment using the hepatocarcinogen N-nitrosomorpholine, as well as glycogenotic and related lesions, hepatocellular foci with a different histochemical pattern were identified. The outstanding features of these hepatic foci, which may progress to hepatocellular adenoma, were increased activities of mitochondrial glycerol-3-phosphate dehydrogenase (mG3PD), glycogen synthase, pyruvate kinase and glucose-6-phosphatase detected by enzyme histochemistry. Since no decrease in activity of any of the enzymes examined were seen in these foci, compared with normal liver, the term enzymatically hyperactive focus (EHF) is proposed for this type of lesion. Only at the stage of overtly nodular growth did these lesions exhibit some of the characteristic changes seen in nodules developing from glycogenotic foci, namely elevated activities of glucose-6-phosphate dehydrogenase, gamma-glutamyl transferase and glutathione-S-transferase P as well as decreased activities of adenosine-triphosphatase, glucose-6-phosphatase and adenylate cyclase. Some of these enzymes have been used widely in morphometric studies as markers for preneoplastic and neoplastic lesions. The inability to detect early EHF may lead to an underestimation of preneoplastic liver lesions in quantitative studies. Although there are apparent differences in the histochemical patterns of glycogen storing foci and early EHF, these differences tend to disappear during progression to overtly neoplastic lesions. In studies comparing the phenotypic alterations in different types of preneoplastic hepatic lesions, the recognition of EHF may contribute to the distinction of obligatory from facultative phenomena during transformation.
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PMID:Unusual histochemical pattern in preneoplastic hepatic foci characterized by hyperactivity of several enzymes. 256 54

Purified brush border membrane of Cotugnia digonopora showed the presence of a number of phosphohydrolases. Among these, alkaline phosphatase was extremely active. Other enzymes such as glucose-6-phosphatase, fructose-1,6-diphosphatase, cAMP-phosphodiesterase, 5'-nucleotidase and adenosine-triphosphatase were also active. Observations were made on the activities of various ATPases; whereas the enzyme was activated by Ca++ and Mg++ in an additive manner, its sensitivity to ouabain was negligible. Furthermore, in the presence of EDTA the enzyme activity was quite significant. The treatment of isolated brush border membrane with mebendazole, niclosamide and praziquantel in vitro did not alter the activity of these enzymes. However, treatment of intact worms drastically affected the integrity of the membrane.
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PMID:Enzymes of isolated brush border membrane of Cotugnia digonopora, and their insensitivity to anthelmintics in vitro. 299 11

Preneoplastic liver lesions were produced in female Wistar rats by oral administration of 2-acetylaminofluorene for 165 days succeeded by a carcinogen-free standard diet up to 420 days. During the treatment numerous altered hepatic foci (AHF) and hyperplastic nodules (HN) were detected histochemically by a focal decrease or lack of adenosine-5-triphosphatase and glucose-6-phosphatase (G-6-Pase) activities. In addition, the immunohistochemically demonstrable amount of L-type pyruvate kinase was clearly reduced. The histochemically demonstrated decrease of G-6-Pase was substantiated by microbiochemical determination of the enzyme activity in microdissected material. Moreover, during the experimental period a continuous decrease in glucokinase and an increase in hexokinase was detected microbiochemically within AHF and HN. These alterations indicate a shift in the carbohydrate metabolism from gluconeogenesis to glucose utilization and pentose-phosphate-pathway for biosynthesis of nucleic acids. Beside other oncofetal markers, HK may be used as indicator of the early stages of liver carcinogenesis.
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PMID:Decrease in glucokinase and glucose-6-phosphatase and increase in hexokinase in putative preneoplastic lesions of rat liver. 304 Jul 65

Enzymatic activities associated with Golgi apparatus-, endoplasmic reticulum-, plasma membrane-, mitochondria-, and microbody-rich cell fractions isolated from rat liver were determined and used as a basis for estimating fraction purity. Succinic dehydrogenase and cytochrome oxidase (mitochondria) activities were low in the Golgi apparatus-rich fraction. On the basis of glucose-6-phosphatase (endoplasmic reticulum) and 5'-nucleotidase (plasma membrane) activities, the Golgi apparatus-rich fraction obtained directly from sucrose gradients was estimated to contain no more than 10% endoplasmic reticulum- and 11% plasma membrane-derived material. Total protein contribution of endoplasmic reticulum, mitochondria, plasma membrane, microbodies (uric acid oxidase), and lysosomes (acid phosphatase) to the Golgi apparatus-rich fraction was estimated to be no more than 20-30% and decreased to less than 10% with further washing. The results show that purified Golgi apparatus fractions isolated routinely may exceed 80% Golgi apparatus-derived material. Nucleoside di- and triphosphatase activities were enriched 2-3-fold in the Golgi apparatus fraction relative to the total homogenate, and of a total of more than 25 enzyme-substrate combinations reported, only thiamine pyrophosphatase showed a significantly greater enrichment.
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PMID:Isolation of a Golgi apparatus-rich fraction from rat liver. II. Enzymatic characterization and comparison with other cell fractions. 431 70

Enzyme biochemical and histochemical assays during chemical carcinogenesis in rat liver have revealed that several adult enzyme activities are lost and some fetal enzyme activities are re-expressed in the hyperplastic foci as well as in the developed hepatomas. How these enzyme alterations are acquired and to what extent these changes are specifically related to the growth alterations leading to neoplastic development are decisive questions. Using a carcinogenesis protocol that combines a single dose of diethylnitrosamine and phenobarbital given continuously as the promoting agent and by assaying serial liver sections for glucose-6-phosphatase, adenosine-5'-triphosphatase and 5'-nucleotidase, we have identified the three-enzyme pattern of 1,746 islands and measured their section areas. We found a clear trend that clones with more deviated enzyme pattern grow faster than less deviated ones.
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PMID:Enzyme pattern and growth rate of liver preneoplastic clones during carcinogenesis by diethylnitrosamine. 608 33

A marked heterogeneity of enzyme histochemical phenotypes was demonstrated in 48 primary hepatocellular carcinomas induced by feeding 2-acetylaminofluorene to rats. All eight possible combinations of three abnormal traits, gain of gamma-glutamyl transpeptidase activity, loss of adenosine-5'-triphosphatase activity, and loss of glucose-6-phosphatase activity, were represented among the hepatocellular carcinomas. The four combinations in which two or three traits occurred together were seen in 85% of the carcinomas, while those categories with a normal phenotype or containing only single marker changes contained the few remaining neoplasms. As expected, the carcinomas all showed greatly increased and variable [3H]thymidine labeling indices; however, neither the rates of cell replication or the degrees of differentiation of the carcinomas appeared to correlate in any meaningful way with the patterns of phenotypic diversity. The distribution of histochemical phenotypes in the carcinomas differs greatly from that reported for enzyme-altered hyperplastic islands induced by carcinogens, but the significance of the difference is not apparent at the present time.
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PMID:Enzyme histochemical phenotypes in primary hepatocellular carcinomas. 611 49

Electron microscopy cytochemistry has been used to study the cytoplasmic location of liposomes and lipid vesicles following specific antibody-dependent phagocytosis. The vesicle compositions were 94-99 mol% 'fluid' lipid (egg phosphatidylcholine or dimyristoylphosphatidylcholine at 37 degrees C or 'solid' lipid (dipalmitoylphosphatidylcholine at 37 degrees C). In some cases, 4 mol% phosphatidylserine was included in the vesicle membrane so as to vary the surface charge density. These vesicles undergo specific antibody-dependent phagocytosis by RAW264 macrophages when the lipid membranes contain 1-2 mol% dinitrophenyl lipid hapten in the presence of rabbit anti-dinitrophenyl IgG antibody. Internalized lipid vesicles can be visualized with the electron microscope when ferritin is trapped in the internal aqueous compartments prior to internalization. The lipid vesicles were demonstrated to be internal to the macrophage plasma membranes by selectively staining the plasma membranes with Ruthenium red. The cytoplasmic location of vesicles and liposomes was studied by electron microscopic staining for activities of the following enzymes: (1) acid phosphatase; (2) inorganic trimetaphosphatase; (3) adenosine triphosphatase; and (4) glucose-6-phosphatase. The first two enzymatic activities were found in association with ferritin-containing vesicles after antibody-dependent phagocytosis, showing the formation of vesicle-containing phagolysosomes. Adenosine triphosphatase and glucose-6-phosphatase were primary not associated with the vesicles, suggesting a minimal association of vesicles with plasma membrane, Golgi, endoplasmic reticulum and perinuclear cisternae. Phagosome-lysosome fusion did not appear to depend on the type of target lipid vesicle or liposome, on the 'fluidity' of the target membrane, or the presence of phosphatidylserine in the target membrane.
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PMID:Cytochemical study of liposome and lipid vesicle phagocytosis. 668 37


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