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)

Plumbagin (5-hydroxy-2-methyl-1,4-naphthoquinone) isolated from Plumbago zeylanica Linn, when administered orally, at a dosage of 4 mg/kg body weight induces tumour regression in 3-methyl-4-dimethyl aminoazobenzene (3MeDAB) induced hepatoma in Wistar male rats. The purpose of this investigation was to identify the changes in the rate of glycolysis and gluconeogenesis in tumour-bearing rats and the effects of treatment with Plumbagin. The levels of certain glycolytic enzymes, namely, hexokinase; phosphoglucoisomerase; and aldolase levels increased (p < 0.001) in hepatoma bearing rats, whereas they decreased in Plumbagin administered rats to near normal levels. Certain gluconeogenic enzymes, namely, glucose-6-phosphatase and fructose-1,6-diphosphatase decreased (p < 0.001) in tumour hosts, whereas Plumbagin administration increased the gluconeogenic enzyme levels in the treated animals. These investigations indicate the molecular basis of the different biological behaviour of 3MeDAB induced hepatoma and the anticarcinogenic property of Plumbagin against hepatoma studied in rats.
Mol Cell Biochem 1993 Aug 11
PMID:Effect of Plumbagin on some glucose metabolising enzymes studied in rats in experimental hepatoma. 826 73

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.
Mol Cell Biochem 1993 May 12
PMID:Changes in the glucose-6-phosphatase complex in hepatomas. 839 4

Thick biological specimens prepared as whole mount cultured cells stained with histochemical reactions, such as thiamine pyrophosphatase, glucose-6-phosphatase, cytochrome oxidase, acid phosphatase, DAB reactions demonstrating specific cell organelles such as Golgi apparatus, endoplasmic reticulum, mitochondria, lysosomes, peroxisomes and pinocytotic vesicles, were observed by ultrahigh voltage electron microscopy at accelerating voltages of 400-1000 kV producing stereo-pairs. As a result, those cell organelles were observed 3-dimensionally and the relative relationships between these organelles demonstrated.
Cell Mol Biol (Noisy-le-grand) 1995 Sep
PMID:Three dimensional observation of whole mount cultured cells stained with histochemical reactions by ultrahigh voltage electron microscopy. 853 71

Glucose-6-phosphate hydrolysis was measured in a fraction obtained from rabbit fast-twitch skeletal muscle and corresponding to total sarcoplasmic reticulum, as well as in three subfractions containing longitudinal tubules, terminal cisternae or both structures. In all cases the levels of hydrolysis measured both in native and disrupted membranes were approximately 60-100 times lower than the microsomal glucose-6-phosphatase activity of the corresponding livers. In contrast to liver microsomes, most (up to 80%) of the glucose-6-phosphate hydrolysing activity in muscle sarcoplasmic reticulum membranes was not inactivated by pH 5.0 pre-incubation indicating that it was not catalysed by the specific glucose-6-phosphatase enzyme. Osmotically induced changes in light-scattering intensity of sarcoplasmic reticulum vesicles revealed that, in contrast to liver microsomes, sarcoplasmic reticulum vesicles were not selectively permeable to glucose-6-phosphate as mannose-6-phosphate was also permeable and in addition they were poorly permeable to glucose. Immunoblot experiments using antibodies raised against the glucose-6-phosphatase enzyme, and liver endoplasmic reticulum glucose and Pi translocases, failed to detect the presence of these protein components in sarcoplasmic reticulum membranes. Southern blot analysis of reverse transcriptase-polymerase chain reaction products from rat muscle revealed that glucose-6-phosphatase mRNA is present in muscle. Quantification of Northern blot analysis of liver and muscle mRNA indicated that muscle contains less than 2% of the amount of glucose-6-phosphate mRNA found in corresponding livers. We conclude that very low levels of specific glucose-6-phosphatase (e.g. as in liver; E.C. 3.1.3.9) are present in muscle sarcoplasmic reticulum and that the muscle and liver glucose-6-phosphatase systems have several different properties.
Mol Membr Biol
PMID:Low levels of glucose-6-phosphate hydrolysis in the sarcoplasmic reticulum of skeletal muscle: involvement of glucose-6-phosphatase. 883 54

In the present report changes in the mRNA level of glucose-6-phosphatase (G6Pase; EC 3.1.39) in newborn and adult dogs in vivo were studied to further test the hypotheses that neonatal hyperglycemia may be due to unsuppressed gluconeogenesis by insulin and that the antidiabetic role of insulin-like growth factor-1 (IGF-1) may be intact in newborn dogs who have consistently demonstrated insulin resistance. Our results were the following: (i) Both renal and hepatic G6Pase mRNA were expressed at birth and increased with time during a 24-h period of fasting after birth. (ii) The renal G6Pase mRNA levels in newborn dogs did not respond to either insulin or epinephrine. (iii) Hyperinsulinemia lowered the liver G6Pase mRNA by only 16.3% in newborn dogs, but reduced the liver G6Pase mRNA to an undetectable level in adult dogs. (iv) Hyperglycemia decreased the hepatic G6Pase mRNA by 14.3% in newborn dogs under hyperinsulinemia. (v) Infused epinephrine did not elevate the hepatic G6Pase mRNA level in newborn dogs in the presence of hyperglycemia and hyperinsulinemia. (vi) In newborn dogs, hyper-IGF-1 rapidly reduced the hepatic G6Pase mRNA level by 50%, and hypoglycemia was unable to elevate the hepatic G6Pase mRNA level under the hyper-IGF-1. We concluded that the reduced rate of suppression of transcription of the liver G6Pase gene by insulin in newborn dogs may reflect the unsuppressed neonatal hepatic gluconeogenesis due to insulin resistance and that the physiological roles of IGF-1 seemed to be intact in newborn dogs and may be not responsible for neonatal hyperglycemia.
Biochem Mol Med 1997 Apr
PMID:Insulin resistance and the transcription of the glucose-6-phosphatase gene in newborn dogs. 916 94

Two Maltese puppies with massive hepatomegaly and failure to thrive had isolated deficient glucose-6-phosphatase (G-6-Pase) activity in liver and kidney and pathological findings compatible with GSD-Ia. To identify the mutation, we cloned G-6-Pase canine cDNA by RT-PCR with primers from the murine G-6-Pase gene sequence. The canine G-6-Pase cDNA is 2346 bp, with a 5' untranslated region of 87 bp, a coding region of 1071 bp, and a 3' untranslated region of 1185 bp. The difference between the canine and human sequences is in the 3' untranslated region. A greater than 90% amino acid sequence homology was seen with canine, human, murine, and rat G-6-Pase. G-6-Pase cDNA from affected and control puppies revealed complete homology except at nt position 450, which showed a guanine to cytosine (G to C) transversion resulting in substitution of a methionine by isoleucine at codon 121 (M121I) in all five clones studied. The loss of an NcoI restriction site on genomic DNA amplified with primers flanking the mutation allowed us to prove that affected puppies were homozygous for the mutation and parents were heterozygous carriers. The mutant G-6-Pase cDNA had 15 times less enzyme activity than wild-type cDNA following transient transfection. Northern blot analysis of puppies with GSD-Ia revealed increased G-6-Pase mRNA, compared to normal controls. Increased G-6-Pase mRNA was also seen in normal fasted puppies compared to littermates in the fed state, suggesting that the increased G-6-Pase mRNA is a physiologic response to fasting. This is the first report of a molecularly confirmed naturally occurring animal model of GSD-Ia. The establishment of a breeding colony of this dog strain will facilitate studies on the role of G-6-Pase gene in glucose homeostasis, in pathophysiology of disease, and development of novel therapeutic approaches such as gene therapy.
Biochem Mol Med 1997 Aug
PMID:Isolation and nucleotide sequence of canine glucose-6-phosphatase mRNA: identification of mutation in puppies with glycogen storage disease type Ia. 925 82

Ferrylmyoglobin (ferrylMb) caused inhibition of microsomal glucose-6-phosphatase (G6Pase) during membrane lipid peroxidation. Butylated hydroxytoluene prevented both the inactivation of G6Pase and the lipid peroxidation. Furthermore, ferrylMb was adsorbed on to the membranes and the membrane proteins polymerized during the lipid peroxidation, suggesting that the inactivation of microsomal G6Pase was due to the disturbance of the membrane structure induced by ferrylMb.
Res Commun Mol Pathol Pharmacol 1997 Jun
PMID:Inhibition of microsomal glucose-6-phosphatase induced by ferrylmyoglobin. 926 88

Glucose metabolism of the bovine embryo is low during the first cleavages and increases sharply after the major resumption of the genome (8-16 cells). The mRNA level for genes involved in glucose metabolism was tested by RT-PCR on individual oocytes and embryos at different stages of development. These genes were: glucose transport GLUT-1, hexokinase (HK), glucose-6-phosphatase-dehydrogenase (G6PDH), and glucose-phosphate-isomerase (GPI); actin was used as a reference transcript. RT-PCR results revealed three types of oocytes or embryos: positive with a PCR signal for each transcript considered, nul with no signal for any transcript, and heterogeneous with a PCR signal for some transcripts and none for others. The number of nul and heterogeneous samples was higher for slow than for fast-cleaving embryos (81% vs. 36%), and the proportion of positive embryos increased significantly at the 16-cell and morula stages (P < 0.002), suggesting a correlation between mRNA content and developmental capacity. In positive embryos, GLUT-1 level was reduced by half during maturation and fertilization. Actin and hexokinase mRNA levels decreased during the first cleavages, but significantly increased at the 16-cell and morula stages, respectively. GPI transcript remained stable throughout development, whereas there was a significant rise for G6PDH at the 4-cell stage, perhaps due to a polyadenylation process. Finally, the absence or decrease in intensity of several transcripts at the blastocyst stage suggests suboptimal culture conditions.
Mol Reprod Dev 1997 Oct
PMID:Glucose metabolism during bovine preimplantation development: analysis of gene expression in single oocytes and embryos. 929 71

The effect of acute glutathione (GSH) depletion induced by GSH-depleting agent L-buthionine-(S,R)-sulfoximine (BSO) on hepatic microsomal glucose-6-phosphatase (G6Pase) activity in male Wistar rats was investigated. Liver GSH evaluated in high-performance liquid chromatography after administration of 4 mmol.Kg-1 BSO i.p. was decreased by 19% and 50% at the time-points of 1.5 h and 3 h, respectively. In these conditions, a significant decrease in Vmax and an increasing trend in K(m) of hepatic G6Pase activity were observed, especially in 3 h BSO-rats. Alterations in kinetic parameters of G6Pase were calculated in both intact and detergent-treated microsomes, using glucose-6-phosphate and pyrophosphate as substrate. A little increase in thiobarbituric acid-reactive substances and a limited decrease in 5,5'-dithiobis(2-nitrobenzoate)-reactive protein thiols were also noted. The results of this study show that acute GSH depletion induced by BSO is able to affect hepatic microsomal G6Pase activity. A possible explanation to account for the effect of BSO-induced GSH depletion on hepatic G6Pase system is discussed.
Res Commun Mol Pathol Pharmacol 1997 Nov
PMID:Effects of acute glutathione depletion induced by L-buthionine-(S,R)-sulfoximine on rat liver glucose-6-phosphatase activity. 946 25

Curcumin, the coloring principle of the commonly used spice turmeric (Curcuma longa) was fed at 0.5% in the diet to streptozotocin-induced diabetic Wistar rats for 8 weeks. Renal damage was assessed by the amount of proteins excreted in the urine and the extent of leaching of renal tubular enzymes: NAG, LDH, AsAT, AlAT, alkaline and acid phosphatases. The integrity of kidney was assessed by measuring the activities of several key enzymes of the renal tissue: glucose-6-phosphate dehydrogenase, glucose-6-phosphatase, and LDH (Carbohydrate metabolism), aldose reductase and sorbitol dehydrogenase (polyol pathway), transaminases, ATPases and membrane PUFA/SFA ratio (membrane integrity). Data on enzymuria, albuminuria, activity of kidney ATPases and fatty acid composition of renal membranes in diabetic condition suggested that dietary curcumin brought about significant beneficial modulation of the progression of renal lesions in diabetes. These findings were also corroborated by histological examination of kidney sections. It is inferred that this beneficial ameliorating influence of dietary curcumin on diabetic nephropathy is possibly mediated through its ability to lower blood cholesterol levels.
Mol Cell Biochem 1998 Apr
PMID:Amelioration of renal lesions associated with diabetes by dietary curcumin in streptozotocin diabetic rats. 956 45


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