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)

D-Galactosamine (800 mg/kg, intraperitoneally) caused significant decrease in the activities of 5'-nucleotidase, glucose-6-phosphatase and cytochrome P450 and increase in activities of gamma-glutamyl transpeptidase, succinate dehydrogenase, acid phosphatase and acid ribonuclease in liver after 24 hr. The levels of RNA, protein and glycogen decreased while total lipids, phospholipids, cholesterol and lipid peroxides increased. It also increased the serum levels of transaminases, alkaline phosphatase and bilirubin while protein concentration decreased significantly. Oral administration of Picroliv (12 mg/kg/day for 7 days), a standardised iridoid glycoside fraction of Picrorhiza kurroa, significantly prevented the biochemical changes in liver and serum of galactosamine-toxicated rats. Kutkoside (12 mg/kg/day for 7 days) also protected against changes in most of the hepatic and serum constituents studied. Another iridoid glycoside from Picroliv, Picroside I, at the same dose level could only prevent toxicant-induced changes in acid phosphatase, phospholipids and lipid peroxides in liver and alkaline phosphatase in serum. Mixture of Picroside I and Kutkoside in the ratio of 1:1.5 at 12 mg/kg dose elicited lesser response than Picroliv.
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PMID:Picroliv and its components kutkoside and picroside I protect liver against galactosamine-induced damage in rats. 133 78

The modifying action of chronic liver injury on the process of hepatocarcinogenesis was investigated. To induce cirrhosis or fibrosis F344 rats received CCl4 alone or in combination with phenobarbital, either before (model 1) or after (model 2) the application of initiator, diethylnitrosamine (DENA). In these models, morphology, tumor incidence as well as polysubstrate monooxygenase system, gamma-glutamyltransferase (GGT) and glucose-6-phosphatase (G-6-Pase) were studied. The data presented show that in model 1 the tumor incidence was much lower than in rats treated with DENA alone. This reduction appeared to be associated with the decrease in cytochrome P450 content occurring in model 1 after DENA administration. Promotion of the hepatocarcinogenic process was observed when CCl4 injury followed the application of DENA (model 2). Comparison of marker enzymes in cirrhotic livers and in tumors either with or without cirrhosis indicated that changes in cytochrome P450 and G-6-Pase were rather the results of parenchymal damage, while GGT was elevated only in tumorous livers. In tumorous livers none of the xenobiotic metabolizing activities decreased as much as the cytochrome P450 content of the same samples. Thus conceivably the cytochrome P450 operates more rapidly in tumors than in normal livers.
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PMID:Modification of DENA-induced hepatocarcinogenesis by CCl4 cirrhosis. Comparison of the marker enzyme patterns. 135 Feb 34

Male C3H/He, B6C3F1 and C57BL/6J mice were given a single injection of diethylnitrosamine (20 micrograms/g body wt) on day 15 after birth and animals were killed 17-29 (C3H/He and B6C3F1) and 29-46 weeks (C57BL/6J) after treatment. Carcinogen-induced liver lesions were identified by a deficiency in the marker enzyme glucose-6-phosphatase and the enzymatic phenotypes of these lesions were studied by enzyme and immunohistochemical methods using serial liver sections stained for seven additional histochemical markers. In all three mouse strains, liver lesions were characterized by an increased basophilia and a decreased expression of UDP-glucuronosyl-transferase, microsomal epoxide hydrolase and NADPH-cytochrome P450 reductase, while the cytochrome P450 isoenzymes 1A2, 2C6 and 2E1 were virtually unexpressed. Quantitative analyses revealed that throughout all periods of investigation, on average greater than 70% of the glucose-6-phosphatase-deficient lesions occupying up to 99% of the total volumetric fraction expressed concomitant alterations in at least one of these additional marker stainings. Upon determination of the phenotypic complexity levels, between 70 and 90% of lesions were found to contain alterations in at least six of the markers analysed, while lesions with alterations in less than three markers were comparatively infrequent. In the light of previous observations in the rat liver system, the relative homogeneity of enzyme phenotypes and the apparent lack of time-dependent changes in enzyme expression suggest that the majority of lesions of all three mouse strains possess an increased neoplastic character already from the very early beginning of the carcinogenic process in liver.
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PMID:Enzyme and immunohistochemical phenotyping of diethylnitrosamine-induced liver lesions of male C3H/He, B6C3F1 and C57BL/6J mice. 157 19

The study investigated the relationship between lipid peroxidation and enzyme inactivation in rat hepatic microsomes and whether prior inactivation of aldehyde dehydrogenase (ALDH) exacerbated inactivation of other enzymes. In microsomes incubated with 2.5 microM iron as ferric sulfate and 50 microM ascorbate, ALDH, glucose-6-phosphatase (G6Pase) and cytochrome P450 (Cyt-P450) levels decreased rapidly and concurrently with increased levels of thiobarbituric acid-reactive substances. Microsomal glutathione S-transferase and nicotinamide adenine dinucleotide phosphate-cytochrome c reductase were little affected during 1 hr of incubation. Addition of reduced glutathione partially protected and N,N'-diphenyl-p-phenylenediamine and butylated hydroxytoluene completely protected microsomes against inactivation of ALDH, G6Pase and Cyt-P450, as well as lipid peroxidation induced by iron and ascorbate. ALDH was more susceptible than G6Pase to inactivation by iron and ascorbate, and was thus an excellent marker for oxidative stress. Inhibition of ALDH by cyanamide injection of rats exacerbated the inactivation of G6Pase in microsomes incubated with 0.1 mM, but not 25 microM 4-hydroxynonenal (4-HN). 4-HN did not stimulate lipid peroxidation. Thus, 4-HN may play a minor role in microsomal enzyme inactivation. In contrast, lipid peroxyl radicals play an important role in microsomal enzyme inactivation, as evidenced by the prevention of both lipid peroxidation and enzyme inactivation by chain-breaking antioxidants.
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PMID:Glutathione and antioxidants protect microsomes against lipid peroxidation and enzyme inactivation. 160 2

Monocrotaline, a pyrrolizidine alkaloid, caused changes in most of the biochemical parameters in rats 12 days after a single dose of 120 mg/kg. These included significantly increased activities of hepatic succinate dehydrogenase, acid ribonuclease, acid phosphatase, gammaglutamyl transpeptidase and 5'-nucleotidase and decreased in the activities of glucose-6-phosphatase and cytochrome P450. The levels of DNA, RNA and glycogen in liver and albumin and protein in serum decreased while serum bilirubin increased. The histopathological changes in liver were characterized by diffused hepatocyte alterations in the form of ballooning, granular cytoplasm, indistinct cell outlines, nuclear changes, focal necrosis, and vascular damage. When picroliv, a standardized iridoid glycoside fraction of Picrorhiza kurroa, was administered orally in a dose of 25 mg/kg simultaneously with monocrotaline, alterations in most of the biochemical parameters along with the histopathological changes in liver caused by monocrotaline were prevented.
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PMID:Picroliv protects against monocrotaline-induced hepatic damage in rats. 190 81

Experimental infection of golden hamsters with the hookworm, Ancylostoma ceylanicum, caused a profound decline in the hepatic microsomal cytochrome P450 content. Concomitant decrease was also noticed in aminopyrine N-demethylase and benzo[a]pyrene hydroxylase activities. However, aniline hydroxylase activity was only marginally elevated during the infection. Microsomal markers, viz., cytochrome b5, NADH-cytochrome-c reductase, and glucose-6-phosphatase, were not significantly altered. Hepatic tissue exhibited an accumulation of lipids, especially phospholipids, triglycerides, and cholesterol, resulting in fatty necrosis around the central vein region. Isolated hepatic microsomes showed a decrease in phosphatidylcholine content. Impairment in hepatic mixed function oxidase (MFO) activities was further confirmed by prolongation in hexobarbital sleeping time and zoxazolamine-induced paralysis. The hepatic MFO system of A. ceylanicum-infected hamsters responded qualitatively and quantitatively in a manner similar to that of control hamsters, upon stimulation with selective chemical inducers like phenobarbitone and 3-methylcholanthrene. Kinetic and in vitro substrate binding studies revealed that for aminopyrine the substrate affinity and the maximum enzyme activity (Vmax) were decreased, while for aniline the binding affinity was decreased and the binding capacity was enhanced. Results indicate specific/selective impairment of the hepatic microsomal cytochrome P450 system during hookworm infection and may have many practical implications in toxicology and pharmacology.
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PMID:Hepatic microsomal cytochrome P450 system during experimental hookworm infection. 236 36

The authors have studied the character of changes in the content of cytochrome P450 and b5, in the oxidation rate of amidopyrine, dimethyl-aniline and aniline, in the NADPH- and ascorbate-dependent lipid peroxidation systems, as well as in glucose-6-phosphatase and acetylesterase activities in the liver microsomes of the rats on semisynthetic diets, including 50% (according to calorific value) of butter or sunflower oil, or receiving fat-free diet (0.5% of sunflower oil) in different terms (4 and 70 days) after a single intragastric administration of a mixture of polychlorinated diphenyls, chlorinated biphenyl (500 mg/kg). It is shown that the degree and character of the microsomal enzymes studied, as well as the changes in the liver structure under the action of chlorinated biphenyl depend, to a certain extent, on the quality and quantity of fat in the diet.
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PMID:[The effect of a lipid food component on enzymatic activity of rat liver endoplasmic reticulum upon the action of polychlorinated biphenyls]. 249 85

We previously reported that phenylmethylsulfonyl fluoride (PMSF) administration to rats (100 mg/kg, ip in olive oil) as late as 6 or 10 hr after CCl4 (1 ml/kg, ip as a 20% v/v solution in olive oil) can partially prevent the necrogenic response to the hepatotoxin at 24 hr. Here we confirm that observation by electron microscopy and provide further evidence that only in these circumstances were nuclear clumping of chromatin, slight dilatation of the endoplasmic reticulum, myelin figures and lipid droplets in the cytoplasm, large numbers of lysosomes and peroxisomes, glycogen, and slightly swollen mitochondria observable in the protected animals. A very minor part of the late protective effects of PMSF might be due to the effects of this drug on decreasing the intensity of covalent binding of CCl4-reactive metabolites or the intensity of CCl4-induced lipid peroxidation still occurring 6 or 10 hr after CCl4. PMSF administration did not prevent CCl4-induced decreases in cytochrome P450 content or glucose-6-phosphatase activity but partially prevented CCl4-induced calcium accumulation in liver. PMSF treatment increased glutathione and glycogen content in CCl4-poisoned animals, but did not markedly modify protein/phospholipid synthesis or degradation processes. Results suggest that the late protective effects of PMSF administration in CCl4-induced liver necrosis might be due to a favorable modulation of the calcium-calmodulin system similar to that previously described for other drugs.
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PMID:Further studies on the mechanism of the late protective effects of phenylmethylsulfonyl fluoride on carbon tetrachloride-induced liver necrosis. 254 23

Rat liver nonparenchymal cells (NPC) were prepared by pronase digestion and purified on discontinuous gradients on Nycodenz. Morphological and biochemical characterization of cell suspensions showed that they were free of contamination by hepatocytes. We have confirmed the usefulness of pyruvate kinase activity in monitoring the degree of hepatocyte contamination of NPC and we have derived an equation which allows this carry-over to be calculated. Using highly purified suspensions of NPC we have shown that they contain glucose-6-phosphatase in low but detectable levels. Spectrophotometric studies showed that they contain cytochrome P450, with a specific content of 24 +/- 5 pmole mg-1 cell protein. A potential source of error in previous studies was recognized; namely that peroxidase, present in NPC in high concentration, is able to mask the absorption due to cytochrome P450. Both the presence and inducibility of this enzyme in NPC prepared from rats pretreated with phenobarbital or 3-methylcholanthrene have been confirmed using Western blot analysis.
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PMID:Cytochrome P450 in highly purified suspension of nonparenchymal liver cells. 260 70

We aim to evaluate the effects of phenobarbital (PB) on the liver drug metabolism, NADPH production capacity and terminal gluconeogenic enzyme, glucose-6-phosphatase (G6Pase) activity in the diabetic state associated with genetic obesity in mice. The results showed that PB treatment increased the amount of liver total cytochrome P450 (cytP450), a drug metabolizing monooxygenase enzyme in genetically obese, hyperglycemic (ob/ob) mice 6-fold and the total activities of other monooxygenase enzymes NADPH cytP450 reductase and 7-ethoxyresorufin O-deethylase (ERDE) 2- and 6.5-fold, respectively. In addition, the regimen increased the liver total activities of two NADPH generating enzymes, 6-phosphogluconate dehydrogenase (6PGDH) and malic enzyme (ME) in obese mice suggesting that the regimen enhanced liver NADPH production capacity in the animals. The data further showed that PB treatment decreased the high hepatic G6Pase activity in obese mice. Both enhanced NADPH generating enzyme activities and lowered G6Pase activity may suppress hepatic glucose output. Since NADPH is required for drug oxidation reactions as a reducing cofactor, high NADPH generating capacity may facilitate liver drug metabolism in vivo. Although the diabetic state in obese mice differs somewhat from that seen in non-insulin dependent diabetic subjects (NIDDs), these findings provide some knowledge about the possible biochemical mechanisms whereby PB treatment normalizes drug metabolism and glycemic control in NIDDs, as has been noted in previous studies.
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PMID:Hepatic drug metabolism and the activities of NADPH generating enzymes and glucose-6-phosphatase in phenobarbital treated genetically obese (ob/ob) mice. 283 24


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