Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.3.9 (glucose-6-phosphatase)
 3,081 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous studies have demonstrated that the hepatotoxin carbon tetrachloride rapidly promotes lipid peroxidation and inhibits microsomal calcium sequestration, microsomal glucose-6-phosphatase activity and cytochrome P-450. Due to its profound effects on lipid peroxidation, we have examined the oral administration of 2.5 ml/kg carbon tetrachloride on the urinary excretion of the lipid metabolites formaldehyde, malondialdehyde, acetaldehyde and acetone. Urine samples were collected up to 48 h after treatment. The urinary metabolites were identified and quantitated by gas chromatography-mass spectrometry and high-pressure liquid chromatography. Time-dependent increases in the urinary excretion of the four metabolites were observed after carbon tetrachloride administration. At 48 h after treatment, the increases in the excretion of malondialdehyde, formaldehyde, acetaldehyde and acetone were approximately 55, 78, 57 and 268%, respectively, relative to control values. The data were expressed in nanomoles per kilogram body weight per 4.5 h. The results clearly demonstrate that carbon tetrachloride increases the urinary excretion of four lipid metabolites which may serve as noninvasive biomarkers of xenobiotic-induced lipid peroxidation.
Pharmacology 1993 Sep
PMID:Carbon-tetrachloride-induced urinary excretion of formaldehyde, malondialdehyde, acetaldehyde and acetone in rats. 841 71

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

Glycogen storage disease type Ia (GSD-Ia) (von Gierke's disease) was identified in two 47-day-old littermate Maltese puppies. The puppies were presented for necropsy with a history of failure to thrive, mental depression, and poor body condition. Gross findings included small body size and emaciation (212 and 246 g versus 595 g for normal littermate), severely enlarged pale livers (48 and 61 g), and pale kidneys. Histologically, there was marked diffuse vacuolation of hepatocytes with large amounts of glycogen and small amounts of lipid. Renal tubular epithelium was mildly to moderately vacuolated. Soft tissue mineralization was present in renal tubules and pulmonary alveolar septa. Biochemical analysis showed that levels of glucose-6-phosphatase were markedly reduced in liver (0.3 and 0.4 microM/minute/g tissue versus 4.7 +/- 1.5 microM/minute/g tissue for controls) and kidney (0.45 and 0.4 microM/minute/g tissue versus 4.1 microM/minute/g tissue for controls) and that glycogen content was increased in liver (9.4% and 9.4% versus 1.3% +/- 1.4% for controls). This is the first confirmed report of animals with glycogen storage disease type Ia.
Vet Pathol 1995 Sep
PMID:Glycogen storage disease type Ia in two littermate Maltese puppies. 857 35

Glycogen storage disease type 1a (GSD 1a), a severe metabolic disorder, is caused by the absence of glucose-6-phosphatase (G6Pase) activity. Diagnosis is currently established by demonstrating the lack of G6Pase activity in the patient's liver specimen. Enzymatic diagnosis cannot be performed in chorionic villi or amniocytes as G6Pase is active only in the liver, kidney, and intestinal mucosa. Recent cloning of the G6Pase gene and subsequent identification of the mutations causing GSD 1a have led to the possibility of performing DNA-based diagnosis in chorionic villus samples (CVS) or amniocytes. Here we report the first DNA-based prenatal diagnosis in two families in whom GSD 1a patients were diagnosed. In one Jewish family with a previously identified R83C mutation, single-stranded conformation polymorphism (SSCP) analysis of the DNA extracted from CVS showed a homozygous R83C mutant pattern. As a result, the pregnancy was terminated and the diagnosis was confirmed on DNA analysis of the aborted fetus. In another family of Arabic extraction in which a V166G mutation has been identified in one of the siblings, SSCP analysis performed on DNA extracted from CVS presented the pattern of a normal control. The pregnancy was carried to term and a healthy baby was born. Thus, once mutations causing the disease are identified, prenatal diagnosis of GSD 1a is possible. SSCP analysis of DNA prepared from CVS is reliable, simple and fast, making it a suitable method for prenatal diagnosis.
Prenat Diagn 1996 Sep
PMID:Prenatal diagnosis of glycogen storage disease type 1a by single stranded conformation polymorphism (SSCP). 890 2

Work on the glucose-6-phosphatase system has intensified and diversified extensively in the past 3 years. The gene for the catalytic unit of the liver enzyme has been cloned from three species, and regulation at the level of gene expression is being studied in several laboratories worldwide. More than 20 sites of mutation in the catalytic unit protein have been demonstrated to underlie glycogenesis type 1a. inhibition of glucose-6-P hydrolysis by several newly identified competitive and time-dependent, irreversible inhibitors has been demonstrated and in several instances the predicted effects on liver glycogen formation and/or breakdown and on blood glucose production have been shown. Refinements in and additions to the presently dominant "substrate transport-catalytic unit" topological model for the glucose-6-phosphatase system have been made. A new model alternative to this, based on the "combined conformational flexibility-substrate transport" concept, has emerged. Experimental evidence for the phosphorylation of glucose in liver by high-K(m),glucose enzyme(s) in addition to glucokinase has continued to emerge, and new in vitro evidence supportive of biosynthetic functions of the glucose-6-phosphatase system in this role has appeared. High levels of multifunctional glucose-6-phosphatase have been shown present in pancreatic islet beta cells. Glucose-6-P has been established as the likely insulin secretagog in beta cells. Interesting differences in the temporal responses of glucose-6-phosphatase in kidney and liver have been demonstrated. An initial attempt is made here to meld the hepatic and pancreatic islet beta-cell glucose-6-phosphatase systems, and to a lesser extent the kidney tubular and small intestinal mucosal glucose-6-phosphatase systems into an integrated, coordinated mechanism involved in whole-body glucose homeostasis in health and disease.
Proc Soc Exp Biol Med 1997 Sep
PMID:Glucose-6-phosphatase structure, regulation, and function: an update. 927 Jul 16

Cultured astroglial cells are able to utilize the monosaccharides glucose, mannose, or fructose as well as the sugar alcohol sorbitol as energy fuel. Astroglial uptake of the aldoses is carrier-mediated, whereas a non-saturable transport mechanism is operating for fructose and sorbitol. The first metabolic step for all sugars, including fructose being generated by enzymatic oxidation of sorbitol, is phosphorylation by hexokinase. Besides glucose only mannose may serve as substrate for build-up of astroglial glycogen. Whereas glycogen synthase appears to be present in astrocytes as well as neurons, the exclusive localization of glycogen phosphorylase in astrocytes and ependymal cells of central nervous tissue correlates well with the occurrence of glycogen in these cells. The identification of lactic acid rather than glucose as degradation product of astroglial glycogen appears to render the presence of glucose-6-phosphatase in cultured astrocytes an enigma. The colocalization of pyruvate carboxylase, phosphenolpyruvate carboxykinase and fructose-1,6-bisphosphatase points to astrocytes as being the gluconeogenic cell type of the CNS.
Glia 1997 Sep
PMID:Metabolic pathways for glucose in astrocytes. 929 44

A protocol was developed to isolate and enrich single renal proximal tubular cells, performing the following steps: in situ kidney perfusion; isolation of renal tissue pieces by collagenase digestion; selective enrichment of proximal tubular fragments by Percoll gradient centrifugation; and isolation of single proximal tubular cells by digestion of proximal tubular fragments with trypsin. The mean enrichment rate, determined by the glucose-6-phosphatase staining method, was 78.9% with a mean cell viability of 93.8%. After modification of the comet assay protocol, genotoxicity in proximal tubular cells could be investigated. A dose-dependent genotoxic effect of ethyl methanesulphonate in these cells was proven.
Mutat Res 1997 Sep 18
PMID:A new method for the enrichment of single renal proximal tubular cells and their first use in the comet assay. 935 75

The herbal remedy extended by Semecarpus anacardium nut extract against Aflatoxin B1 mediated hepatocellular carcinoma was established by studies on carbohydrate metabolizing enzymes. Since some definite correlation exists between tumour progression and the activities of glycolytic and gluconeogenic enzymes, assessment of alterations in their activity can be used as successful markers of diagnosis and prognosis. The present work compares the activities of glycolytic and gluconeogenic enzymes in hepatocellular carcinoma bearing rats with drug-treated animals. An overall increase in glycolytic enzymes namely hexokinase, phosphoglucoisomerase, and aldolase with a subsequent reduction in gluconeogenic enzymes, glucose-6-phosphatase and fructose-1,6-biphosphatase was observed in plasma and liver homogenates of hepatocellular carcinoma bearing rats. The administration of Semecarpus anacardium nut extract caused a significant decrease in the activity of glycolytic enzymes and an increase in gluconeogenic enzymes' activities to near normal values in drug-treated animals.
Pharmacol Res 1997 Sep
PMID:Modulating effect of Semecarpus anacardium Linn. nut extract on glucose metabolizing enzymes in aflatoxin B1-induced experimental hepatocellular carcinoma. 936 62

Many agents have been used to release the latent portion of the activities catalyzed by the glucose-6-phosphatase (Glc-6-Pase) system. Detergents, which disrupt the microsomal membrane concomitantly with Glc-6-Pase activation, have been the most widely used of these agents. The treatment of microsomes with alamethicin or histone II-A has also been reported to activate the Glc-6-Pase system to the same extent as detergent treatment. While alamethicin reportedly permeabilizes the microsomal membrane (R. Fulceri et al., 1995, Biochem. J. 307, 391-397), conflicting ideas as to histone II-A's mechanism of activation have been described (J. St.-Denis et al., 1995, Biochem. J. 310, 221-224 and J. Blair and A. Burchell, 1988, Biochim. Biophys. Acta 964, 161-167). We further investigated whether activation of the Glc-6-Pase system by histone II-A is due to permeabilization of the microsomal membrane. We treated rat liver microsomes with Triton X-100, alamethicin, or histone II-A and found them to be equally effective in maximally activating the Glc-6-Pase system. We also examined the modifying effects of alamethicin and histone II-A on the sensitivity of Glc-6-Pase activities to inhibition by N-bromoacetylethanolamine phosphate (BAEP) and 3-mercaptopicolinate (3-MP), both thiol-directed reagents. Alamethicin, but not histone II-A, abolished the inhibitory effects of BAEP and 3-MP on activities of the Glc-6-Pase system. Our studies support previous reports of Glc-6-Pase activation by alamethicin via permeabilization of microsomal membranes and histone II-A activation without microsomal membrane permeabilization.
Arch Biochem Biophys 1998 Sep 01
PMID:Histone II-A activates the glucose-6-phosphatase system without microsomal membrane permeabilization. 972 Nov 97

The importance of ashwagandha root extract in the regulation of thyroid function with special reference to type-I iodothyronine 5'-monodeiodinase activity in mice liver has been investigated. Although the root extract (1.4 g kg(-1)) administered daily for 20 days by gastric intubation increased serum 3,3',5-triiodothyronine (T3) and tetraiodothyronine (T4) concentrations and hepatic glucose-6-phosphatase activity, hepatic iodothyronine 5'-monodeiodinase activity did not change significantly. Furthermore, ashwagandha root extract significantly reduced hepatic lipid peroxidation, whereas the activity of antioxidant enzymes such as superoxide dismutase and catalase were increased. These findings reveal that the ashwagandha root extract stimulates thyroidal activity and also enhances the antiperoxidation of hepatic tissue.
J Pharm Pharmacol 1998 Sep
PMID:Changes in thyroid hormone concentrations after administration of ashwagandha root extract to adult male mice. 981 Nov 69


<< Previous 1 2 3 4 5 6 7 8 9 10