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)

An oval cell-enriched population was isolated using two isopyknic centrifugation steps in Percoll gradients from the livers of young adult male rats maintained for 6 to 12 weeks on a choline-deficient diet containing 0.05% DL-ethionine. This cell population equilibrated sharply at densities ranging between 1.07 and 1.08 g/ml, possessed a mean cell diameter in fixed-cell smears of 13.6 micron, and showed viabilities of greater than 95% as judged by trypan blue dye exclusion. Contamination of this population by hepatocytes and Kupffer cells was determined to be less than 1% and between 4 and 14%, respectively. gamma-Glutamyl transpeptidase activity was demonstrated both biochemically and histochemically to be the most constant marker for evaluating the oval cell-enriched population isolated at various times over the 6 to 12 weeks of the choline-deficient/DL-ethionine dietary regimen. In contrast, the percentages of nonhepatocytic cells showing labeling for DNA synthesis and for alpha-fetoprotein were both found to be the highest in the oval cell-enriched population isolated at 6 weeks and lowest in that obtained at 12 weeks of dietary treatment. Furthermore, at 10 to 11 weeks, 19.2% of the nonhepatocytic cells in this population were positive for albumin, while 2.1% were positive for glucose-6-phosphatase activity, indicating some cells to be intermediate in function between the oval cell and the hepatocyte. In comparison, hyperplastic bile ductular epithelial cells in tissue preparations isolated from the livers of rats previously subjected to 13 weeks of chronic feeding of the noncarcinogenic cholestatic agent, 1-naphthyl isothiocyanate, or at 8 to 13 weeks following bile duct ligation were found to be strongly positive for gamma-glutamyl transpeptidase activity, as well as to be positive for alkaline phosphatase activity, but to be essentially negative for glucose-6-phosphatase activity, glycogen content, and albumin production. However, an occasional bile ductular cell in these preparations was found to exhibit a strong cytoplasmic binding of [6,7-3H]estradiol, an indirect measure of alpha-fetoprotein production. Also, a low, but demonstrable amount of DNA synthesis was noted in the bile ductular cells present in these preparations. Furthermore, a viable cell population highly enriched in bile ductular epithelial cells was isolated by isopyknic centrifugation in Percoll following enzymatic dissociation of the hyperplastic tissue preparation from bile duct ligated rats.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Isolation and partial characterizations of oval and hyperplastic bile ductular cell-enriched populations from the livers of carcinogen and noncarcinogen-treated rats. 620 45

The usual histologic pattern in acute viral hepatitis (AVH) includes cellular abnormalities predominantly in the perivenular (zone 3) hepatocytes and changes interpreted as representing regenerative activity in the periportal (zone 1) hepatocytes. Enzyme histochemical and ultrastructural studies of livers of 12 patients with AVH were undertaken to see whether these features support the concept of regeneration of hepatocytes in zone 1. The swollen hepatocytes in the perivenular areas were hydropic, with dilated or eccentric rough endoplasmic reticulum and decreased or vesicular smooth endoplasmic reticulum; correspondingly, the glucose-6-phosphatase activity (reflecting, when present, intact and functional endoplasmic reticulum) was markedly decreased. Succinic dehydrogenase and diphosphopyridine nucleotide diaphorase activities, representing mitochondrial enzymes, were limited to the perinuclear or pericanalicular cytoplasm of swollen hepatocytes. gamma-Glutamyl transpeptidase activity was increased. The periportal hydropic hepatocytes were small and arranged in clusters displacing sinusoids. Ultrastructurally, these hepatocytes had nearly normal organelles but scanty smooth endoplasmic reticulum. Activities of the enzymes glucose-6-phosphatase, succinic dehydrogenase, and diphosphopyridine nucleotide diaphorase were weak, although glycogen was abundant. gamma-Glutamyl transpeptidase activity was scanty in these hepatocytes. These findings from enzyme histochemical and electron microscopic studies could be interpreted as evidence of functional deterioration of perivenular swollen hepatocytes and relative functional immaturity of periportal hydropic clustered hepatocytes, suggesting regeneration of zone 1 hepatocytes.
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PMID:Acute viral hepatitis: morphologic and functional correlations in human livers. 669 43

Radiation-induced carcinogenesis of the rat liver using iridium-192 seeds as an intrahepatic radioactive source was studied by enzyme histochemical means. Rats were divided into six groups according to various combinations of one or two iridium-192 or stainless steel seeds and whether they were given a diet containing 0.05% phenobarbital (PB) or a basal diet (BD). Each group were sacrificed at 20, 40, and 60 weeks after intrahepatic insertion of the iridium-192 or stainless steel seeds. gamma-Glutamyl transpeptidase (GGT), glucose-6-phosphatase (G6Pase), and adenosine triphosphatase (ATPase) were stained in the liver tissues, and GGT-positive foci were quantified. Liver neoplasm was not evident, but enzyme-altered foci (EAF) were induced by gamma-ray irradiation. At every point (20, 40, and 60 weeks) after the insertion of the seeds, the GGT-positive area was larger in the rats given than those given BD. Moreover, despite the iridium-192 radioactivity decay, EAF developed continuously in the rats given PB, and persisted in those given BD from 40 to 60 weeks after insertion. These results indicated that phenobarbital promotes the development of EAF initiated by irradiation, as it promotes the process of chemical carcinogenesis in the rat liver.
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PMID:Promoting effects of phenobarbital on the enzyme-altered foci induced by intrahepatic gamma-ray-irradiation in the rat liver. 884 57