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)

We studied the development of liver tumors in male transforming growth factor alpha (TGF-alpha) transgenic mice of the CD1 strain and examined the expression of the transgene by immunohistochemistry and in situ hybridization. Livers of 4-5-week-old transgenic mice contained areas of centribobular hypertrophy with low glucose-6-phosphatase activity. These areas progressively expanded, and hypertrophy and dysplasia became generalized in livers of mice at 10-12 months of age. The expression of the transgene, determined by either immunohistochemistry or in situ hybridization, was uneven in animals that were 10 weeks old or older. The positive hepatocytes formed patches with a predominant centrilobular distribution. We studied a total of 23 liver tumors (7 hepatocellular carcinomas and 16 adenomas) obtained from 11 mice at 13-15 months of age and from one 7-month-old animal which received zinc sulfate to induce the transgene. The carcinomas were well differentiated tumors, without glucose-6-phosphatase or gamma-glutamyltranspeptidase activity, that developed from the dysplastic parenchyma and occasionally within an adenoma. In all carcinomas and in 56% of the adenomas there was overexpression of the transgene in relationship to the surrounding tissue. The majority of the tumors that overexpressed TGF-alpha were alpha-fetoprotein positive, while alpha-fetoprotein staining was not detected in tumors (all adenomas) that did not show excessive transgene expression. We conclude that TGF-alpha functions as a promoter of liver carcinogenesis through its effect as an autocrine inducer of hepatocyte proliferation. Further, the data indicate that TGF-alpha overexpression may favor tumor progression.
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PMID:Development of liver tumors in transforming growth factor alpha transgenic mice. 132 2

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

Characteristic enzyme alterations have been demonstrated during the stages of experimental hepatocarcinogenesis in rats. The activity of gamma-glutamyl transpeptidase (GGTPase) in hyperplastic and neoplastic hepatocytes is usually increased, whereas that of canalicular adenosine triphosphatase (ATPase) and of glucose-6-phosphatase (G6Pase) is more variable. The activities of these marker enzymes were studied by histochemical techniques in 10 human hepatocellular carcinomas (HCCs), 1 liver cell adenoma, and 1 cholangiocarcinoma of liver. In 9 cases, the nontumorous liver was also examined. All HCCs, but not the liver cell adenoma, displayed enzyme patterns that differed from normal. GGTPase activity was markedly increased in 8 HCCs, whereas the activities of G6Pase and ATPase were lost in 6 and 8 HCCs, respectively. These enzyme alterations occurred as 5 of 7 possible combinations, resulting in significant heterogeneity of enzyme phenotypes, similar to that in experimental hepatocarcinogenesis.
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PMID:Enzyme patterns in human hepatocellular carcinoma. 624 71

Individuals with type Ia glycogen storage disease (glucose-6-phosphatase deficiency) frequently develop hepatic adenomas. Potential complications involving these adenomas include malignant transformation and hemorrhage. Five of 9 patients with this disease had evidence of hepatic filling defects on radionucleotide liver scan when first evaluated at our hospital. Dietary therapy aimed at preventing hypoglycemia was begun in 7 of the 9 patients. Prevention of hypoglycemia resulted in the correction of all of the metabolic abnormalities (lactic acidosis, hyperlipidemia, hyperuricemia, and growth retardation). Treatment also corrected the marked elevation in plasma glucagon concentrations. A disappearance of the hepatic lesions occurred in 2 of the treated patients, and a marked reduction in size of the adenoma occurred in the third patient. The hepatic filling defects remained present in the two untreated patients. None of the affected patients receiving dietary therapy have developed hepatic adenomas. One of these patients is now 22 yr old and has received dietary therapy for 7 yr. Early dietary therapy seems to be effective in preventing development of adenomas as well as inducing their resolution.
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PMID:Regression of hepatic adenomas in type Ia glycogen storage disease with dietary therapy. 694 8

Reduced glucose-6-phosphatase, increased GGT activity and reduction of cytochrome P-450 content are considered to be markers of chemical hepatocarcinogenesis in rats. The significance of these changes were studied in certain human liver lesions; adenoma, focal nodular hyperplasia and hepatocellular carcinoma all developed in non-cirrhotic livers. Enzymes showed normal values in 4 out of 5 adenomas, in 2/13 FNH and in 4/18 HCC samples. The decreased cP-450 content in HCC proved to be the most consistent alteration (12/18). Only 3 HCC samples possessed changes off all enzymes. These data suggest that at least those enzymes which are used as markers in rat chemical hepatocarcinogenesis have little or no biological significance in human liver tumors, primarily due to the intertumoral heterogeneity of enzyme activity. Such heterogeneity was observed in the peritumoral "normal" liver tissue, too.
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PMID:Marker Enzymes of Rat Chemical Hepatocarcinogenesis in Human Liver Tumors. 1117 85

A 23-year-old woman was admitted to our hospital with recurrent gouty arthritis. Laboratory findings showed hypoglycemia, lactic acidosis, hyperlipidemia, and hyperuricemia, with normal values of serum alfa-fetoprotein (AFP) and protein induced by vitamin K absence (PIVKA-II). A diagnosis of glycogen storage disease type I (GSD-type I) was made on the basis of the laboratory data, liver biopsy findings, and partially deficient thrombocyte glucose-6-phosphatase (G-6-Pase) activity. Ultrasonography and computed tomography revealed multiple focal hepatic masses. Biopsied specimens of the lesion demonstrated a hepatic adenoma, which changed in appearance in the relatively short period between echography and computed tomography. This interesting phenomenon may highlight the importance for careful follow-up of hepatic adenomas, because of the potential of rupture, hemorrhage, or malignant transformation. During follow-up, the present patient received hemodialysis due to renal failure, and the adenoma regressed spontaneously after 8 years. Included are diagnostic images, demonstrating the association of hepatic adenoma and GSD-type I.
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PMID:Spontaneous regression of hepatic adenoma in a patient with glycogen storage disease type I after hemodialysis: ultrasonographic and CT findings. 1157 51

Glycogen storage diseases (GSDs) or glycogenoses comprise several rare inherited diseases caused by abnormalities of the enzymes that regulate the synthesis or degradation of glycogen. We report on a male patient with type Ia GSD (GSD Ia) who was followed-up for more than 20 years. He had been diagnosed with GSD Ia based on biochemical tests and the glucose-6-phosphatase (G6Pase) enzyme assay from a liver biopsy at 6 years old, due to problems of hepatomegaly, growth retardation, and recurrent hypoglycemic episodes. The introduction of uncooked cornstarch improved his quality of life only in the first 8-year follow-up period. At 17 years old, gouty arthritis with multiple tophi and generalized xanthomatosis developed. Later, hepatocellular adenoma, nephrolithiasis, and gastrointestinal bleeding occurred at the age of 20, 23, and 24 years, respectively. At 26 years old, he suffered from acute renal failure and polyradiculoplexopathy. The problem of delayed puberty persisted. The story of this patient illustrates the multisystemic nature of GSD Ia and highlights the need for careful dietary therapy and long-term follow-up.
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PMID:A 20-year follow-up of a male patient with type Ia glycogen storage disease. 1284 28

The levels of dehydroepiandrosterone (DHEA) and its sulfate (DHEA-S) peak in human in their twenties, then decrease gradually with age. The physiological importance of DHEA was not clear until recent research reports showing that DHEA has beneficial effects on preventing diabetes, malignancy, inflammation, osteoporosis, and collagen disease. We summarize our results concerning diabetes, hepatitis, and colon cancer. In 1982, Coleman et al. [Diabetes 31 (1982) 830] reported that DHEA decreased hyperglycemia in diabetic db/db mice, which become insulin resistant. We measured hepatic gluconeogenic enzymes in an attempt to elucidate the mechanical mechanism of DHEA action. The activity and gene expression of hepatic gluconeogenic enzyme such as glucose-6-phosphatase (G6Pase) was increased in db/db mice despite hyperinsulinemia compared to control db/+m mice. DHEA, like troglitazone, decreased these levels in db/db mice. We also showed that DHEA improved the insulin resistance caused by aging or obesity using the glucose clamp technique in another animal model. In humans, the serum DHEA concentration was shown to be associated with hyperinsulinemia in diabetes. It also became clear that DHEA increased insulin secretion in old-aged db/db mice. DHEA increases not only insulin sensitivity due to the effects in the liver and muscle, but also insulin secretion. As an effect of DHEA on T-cell mediated hepatitis induced by concanavalin A (ConA), DHEA reduced hepatic injury by inhibiting several inflammatory mediators and apoptosis. As an effect of DHEA on carcinogenesis, DHEA would be a potential chemopreventative agent against colon cancer because it decreases the number of azoxymethane (AOM) induced aberrant crypt foci, which is a possible precursor to adenoma and cancer in a murine model.Thus, since DHEA has many beneficial effects experimentally, we should consider administration of DHEA in the future, and common mechanisms among these actions of DHEA should be elucidated in further studies.
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PMID:Prevention of diabetes, hepatic injury, and colon cancer with dehydroepiandrosterone. 1294 37

Glycogen storage disease type I (GSD I) is a metabolic disorder resulting from defects in the glucose-6-phosphatase system. Approximately 75% of adolescent and adult patients develop hepatocellular adenomas, which can lead to considerable morbidity and mortality. The pathogenesis of adenomas is unclear and the risk of developing adenomas in treated patients is uncertain. The objective of this study was to determine whether metabolic imbalance was related to the occurrence of adenomas in patients with GSD I, and to determine what specific biochemical pathways were involved. We performed a 1:1 case-control retrospective study; cases were GSD I patients with adenomas and controls were GSD I patients without adenomas. Controls and cases were matched according to age at diagnosis, age at adenoma detection, and gender. We investigated biochemical abnormalities indicative of metabolic balance and exogenous factors potentially related to the onset of adenomas in the two groups. We detected no significant differences in dietetic treatment, compliance to treatment, or biochemical parameters related to metabolic balance between the two groups. In conclusion, we were unable to identify any significant differences in metabolic balance between GSD I patients who developed adenomas and those who did not.
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PMID:Hepatocellular adenoma and metabolic balance in patients with type Ia glycogen storage disease. 1808 10

Glycogen storage disease (GSD) type Ia is caused by a deficiency in glucose-6-phosphatase. Long-term complications, including renal disease, gout, osteoporosis and pulmonary hypertension, develop in patients with GSD type Ia. In the second or third decade, 22-75% of GSD type Ia patients develop hepatocellular adenoma (HCA). In some of these patients, the HCA evolves into hepatocellular carcinoma. However, little is known about GSD type Ia patients with HCA who develop cholangiocellular carcinoma (CCC). Here, we report for the first time, a patient with GSD type Ia with HCA, in whom intrahepatic CCC was developed.
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PMID:Case of cholangiocellular carcinoma in a patient with glycogen storage disease type Ia. 2490 94


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