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)

Acute renal failure was induced in male rats by the subcutaneous injectioon of 4 mg HgC12 per kg body weight. Enzyme activities of the proximal tubule were studied histochemically at six time intervals from 15 min to 24 h. The enzyme studied were alkaline phosphatase, 5'-nucleotidase, acid phosphatase, alpha-glycerophosphate dehydrogenase (NAD-independent), malic dehydrogenase, succinic dehydrogenase, latic dehydrogenase, glucose-6-phosphate dehydrogenase and glucose-6-phosphatase. Decreases in activity were observed for alkaline phosphatase and 5'-nucleotidase after 15 min. Acid phosphatase was decreased after 30 min. These three enzymes returned to control levels after 3 h, but malic dehydrogenase and alpha-glycerophosphate dehydrogenase were decreased at this time interval. Succinic dehydrogenase was first decreased after 6 h. The earliest morphological changes detectable by light microscopy were observed in pars recta tubules in the medullary rays after 6 h, a time when all enzymes studied showed widespread decreased activity throughout the proximal tubule. After 24 h, the pars convoluta appeared morphologically normal but the pars recta was necrotic and exhibited calcification, whereas enzyme activity was decreased (absent in some cases) in both pars convoluta and pars recta. These results support the hypothesis that Hg++, when given in a sublethal dose, is associated with early histochemical changes in the brush border of the proximal tubule, which may be related to early changes in sodium reabsorption and to the subsequent development of acute renal failure. The observation that changes in plasma membrane-associated enzymes occur early and prior to alterations in enzymes of mitochondria and the endoplasmic reticulum suggests that Hg++ interacts initially with the plasma membrane.
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PMID:Studies on the pathophysiology of acute renal failure. II. A histochemical study of the proximal tubule of the rat following administration of mercuric chloride. 18 27

1. The activity of alkaline phosphatase is intensely positive in proximal tubule I and II during the breeding season. In the kidney of secretion producing the enzyme is detectable as against to kidney of winter on the whole proximal tubule II. 2. In the kidney what is able to build a nest, concentration and size of acid phosphatase granules are very increasing in proximal tubule II. 3. The detection of unspecific esterase was negatively already. 4, The reaction of glucose-6-phosphatase is slightly demonstrable in cells of proximal segment of secretion producing what are enlarged fourfold. 5; From the varied reaction of acid and alkaline phosphatase we conclude that both are to set in relation to excretory activity, but not to process of synthesis in kidney of late-spring fish.
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PMID:[Histological and histochemical studies of the stickleback Gasterosteus aculeatus L. kidney. III. Activity of various phosphatases depending on secretion]. 19 Aug 10

Methods were devised or modified which made it possible to measure phosphoenolpyruvate carboxykinase, fructose-1,6-bisphosphatase, and glucose-6-phosphatase in seven defined parts of single nephrons and in patches from thin limb and papilla areas dissected from freeze-dried microtome sections of rat kidney. All three enzymes were essentially confined to the proximal tubule. In normal kidneys, the levels were highest in the proximal convoluted tubule. Glucose-6-phosphatase was 20 times higher in the early part of the convoluted segment than in the late part of the straight segment. With one exception, in acidosis, only phosphoenolpyruvate carboxykinase increased (fourfold in the proximal convoluted segment but much less in the straight portion). In starvation, phosphoenolpyruvate carboxykinase increased about as much as in acidosis in the proximal straight tubule, but not as much in convoluted portions, whereas glucose-6-phosphatase rose modestly in both parts of the proximal tubule and fructose bisphosphatase rose only in the straight tubule, especially the early segment. It is suggested that ammoniagenesis can accompany gluconeogenesis in the proximal convoluted tubule but not in the straight segment.
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PMID:Distribution along the rat nephron of three enzymes of gluconeogenesis in acidosis and starvation. 21 58

Na-coupled D-glucose transport in rabbits with cis-diamminedichloride platinum (CDDP; cisplatin) induced acute renal failure (ARF) has been studied. ARF occurred at 3 days after injection of CDDP (3 mg/kg i.v.). Na-coupled D-glucose transport into brush-border membrane vesicles (BBMV) from both outer cortex (OC) and outer medulla (OM) of ARF rabbits under zero-trans condition was decreased. Increased Km (i.e., decreased affinity of transport carrier for D-glucose) in OC and decreased Vmax (i.e., decreased number of glucose carrier) in OM were observed in CDDP-induced ARF rabbits. Decrease glucose transport was also observed under equilibrium exchange condition. Intravesicular volume of BBMV from OC and OM of ARF rabbits was decreased. In homogenate and BBMV from OC and OM of ARF rabbits, activities of gamma-glutamyl transpeptidase and alkaline phosphatase (marker enzymes of brush-border membrane) were decreased. Activities of succinate dehydrogenase, glucose-6-phosphatase, and Na-K ATPase (marker enzymes of mitochondria, endoplasmic reticulum, and basal lateral membrane, respectively) were not affected by CDDP administration. These results suggested that one of the main target sites of CDDP in kidney is brush-border membrane (BBM) along the proximal tubule, that is, not only Na-coupled D-glucose transport carrier protein but also other proteins in BBM.
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PMID:Decreased sodium dependent D-glucose transport across renal brush-border membranes in cis-diamminedichloride platinum induced acute renal failure. 156 86

Primary cultures of renal rabbit proximal tubule cells were initiated from a pure suspension of proximal tubule fragments. Proximal tubule cells were grown in a hormone-supplemented, serum-free medium containing low concentrations of antibiotics. Confluent monolayers exhibited multicellular dome formation, indicating the presence of transepithelial solute and water transport. Ultrastructural examination revealed a monolayer of polarized epithelial cells with tight junctions and sparse membraneous microvilli facing the culture medium. Time course biochemical characterization was performed using a palette of 12 enzymes, representative of important metabolic functions or pathways. Brush-border-associated enzymes (gamma-glutamyl transpeptidase and alanine aminopeptidase) were moderately reduced throughout the culture whereas alkaline phosphatase was markedly decreased at confluency. Mitochondrial and lysosomal marker enzymes were well preserved over the culture period. Glutathione-S-transferase activity remained stable during the 16-day culture period investigated. Glycolysis enzyme activities (lactate dehydrogenase and hexokinase) were enhanced, as a function of culture age. Na(+)-K(+)-ATPase activity rise was concomitant with the increase of glycolysis marker enzymes. In contrast, the gluconeogenesis marker enzyme, glucose-6-phosphatase, fell dramatically to reach a low level equivalent to 4% of the activity measured in isolated proximal tubules. Primary cultures exhibited several differentiated functions of the proximal tubule cell: (a) PTH alone was able to induce a significant stimulation of adenylate cyclase activity, unlike isoproterenol, thyrocalcitonin, and arginine vasopressin, and (b) sodium-dependent alpha-methylglucoside (AMG) transport was detected. This AMG uptake was selectively inhibited by phlorizin (5 X 10(-3) M), which is a competitive inhibitor of glucose uptake at the apical membrane. Complete characterization made it possible to investigate hitherto unexplored aspects of in vitro cultured proximal tubule cells. This primary culture model could provide a useful and reliable tool to investigate in vitro renal proximal tubule function, under normal conditions or after a drug-induced toxicity.
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PMID:Biochemical, functional, and morphological characterization of a primary culture of rabbit proximal tubule cells. 167

This is a case of a 15-month-old child suffering from Fanconi-Bickel syndrome, characterized with Fanconi syndrome manifestations (glycosuria, amino aciduria and phosphaturia), and the build-up of glycogen in the liver in a similar manner as seen in cases of glycogenesis type Ia. Due to the presence of liver glycogenosis, the patient also has a tendency towards hypoglycemia, ketonuria, hypercholesterolemia and hypertriglyceridemia. The glycogenosis seen in the patients with the Fanconi-Bickel syndrome, does not depend on a defect in the activity of the glucose-6-phosphatase enzyme, but in fact is due to a defect in the transporter which mobilizes glucose and galactose in the liver and in the basolateral membrane of the proximal tubule of the kidney.
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PMID:[The Fanconi-Bickel syndrome]. 186 46

We describe a novel technique for the histochemical and cytochemical demonstration of glucose-6-phosphatase activity. In this method, lead is replaced by cobalt. After activity of glucose-6-phosphatase, cobalt phosphate Co3(PO4)2 is formed, and in the presence of ammonium sulfide (NH4)2S, the precipitate is transformed into a sulfide that fixes osmium and provides good electron density. Glucose-6-phosphatase activity was determined mostly in rat kidney cells, but controls were also performed in liver cells. A strong reaction was seen in proximal tubule cells, but the reaction was weak in distal convoluted tubule cells. This technique showed the same endoplasmic reticulum (ER) organization in proximal and distal nephron as that seen with the osmium impregnation technique. In collecting tubules, intercalated cells had irregular reactivity, while principal cells had none. Our results indicate that the cobalt technique is valid, reliable, and sensitive enough to detect low glucose-6-phosphatase activity. Moreover, the technique can be used with 1-mm-thick specimens and obviates the need for use of frozen tissue sections.
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PMID:A new method based on cobalt for histochemical and cytochemical demonstration of glucose-6-phosphatase activity. 216 94

High voltage free flow electrophoresis is a carrier-free method used for analytical and preparative cell separation, based on charge surface properties of cells. Two cell populations from the proximal tubule of the rabbit kidney were isolated by free flow electrophoresis from a suspension of pure proximal cells. This single-cell suspension was obtained through an original method by the combination of a Ca-binder action and gentle mechanical treatment associated with several shifting steps, on a pure suspension of isolated proximal tubules. Before the electrophoretic separation, the proximal cell origin was confirmed by enzymatic marker measurements, and the metabolic capacity was assessed by the cell respiratory activity. The isolated cells were very poor in distal tubule marker enzymes and were enriched in proximal tubule marker enzymes. Respiratory measurement showed a high cell metabolic capacity. After the electrophoretic separation, the origin of the cell populations was assessed by measuring specific marker enzymes. The cells in the slow-moving electrophoresis fractions had a high gamma-glutamyl transpeptidase activity and a low glucose-6-phosphatase activity. The fast moving cells showed a high glucose-6-phosphatase content and a poor gamma-glutamyl transpeptidase activity. Cells isolated by free flow electrophoresis were shown to possess long microvilli. This new methodology, allowed for the first time, the separation of a fast-moving cell population originating from the convoluted portion of the proximal tubule and a slow-moving cell population originating from the straight part of the proximal tubule of the rabbit kidney.
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PMID:Preparative free flow electrophoresis for the isolation of two populations of proximal cells from the rabbit kidney. 257 Jun 96

Two cell populations from the proximal tubule of the rabbit kidney were separated by free flow electrophoresis from a pure suspension of proximal tubular cells obtained by a combination of a Ca-binding agent, gentle mechanical forces and differential sifting. Before the electrophoretic separation, distal and proximal enzyme activities were measured on the cortical homogenates, on the proximal tubule suspensions and on the isolated cell samples in order to assess the purity of the cell preparation. The isolated cells were very poor in distal tubule marker activities and were enriched in proximal tubule marker enzymes. Cell oxygen consumption was measured before and after the electrophoretic run were similar and reflected high cell metabolic capacity. The cells in the slow-moving electrophoresis fractions had a high gamma-glutamyl transpeptidase activity and the fast moving cells showed a high glucose-6-phosphatase activity. These results point out a separation of viable cells from straight and convoluted portion of the proximal tubule from the rabbit kidney. These two cell populations can be suitable for further use in biochemical and physiological studies.
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PMID:[Free flow electrophoresis. Application to the separation of 2 populations of proximal tubule cells from the rabbit kidney]. 257 34

Enzyme histochemical techniques were utilized to examine the progression and extent of proximal tubular injury during the development of cis-diamminedichloroplatinum (II) (CDDP)-induced acute renal failure. Acute renal failure was induced in male rats by the intraperitoneal administration of 10 mg CDDP/kg body weight. At 6, 24, 48, 72, and 96 hr following treatment, renal function was assessed and tissue was collected for renal morphologic and enzyme histochemical studies. The enzymes examined were gamma-glutamyl transpeptidase, alkaline phosphatase, sodium-potassium ATPase (nitrophenyl phosphatase), acid phosphatase, glucose-6-phosphatase, succinic dehydrogenase, alpha-glycerophosphate dehydrogenase, and lactic dehydrogenase. By 24 hr, the activity of acid phosphatase was reduced throughout the proximal tubule, with the greatest decrease occurring in the P3 segment of the proximal tubule located in the outer stripe of the outer medulla. Changes in the histochemical staining of the remaining enzymes were not consistently observed until 48 or, in some cases, 72 hr. These alterations involved all portions of the proximal tubule with the most severe changes involving P3. The results of the enzyme histochemical studies along with the morphologic findings indicating that the initiation of CDDP-induced acute renal failure, first apparent at 48 hr in this model, is associated with cell injury throughout the proximal tubule. The majority of the histochemical changes did not become apparent until late in the course of tubular injury. This suggests that most of the changes in enzyme activity represent nonspecific effects of CDDP-induced tubular injury, as opposed to direct enzyme inhibition by the drug.
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PMID:Cis-diamminedichloroplatinum (II)-induced acute renal failure in the rat: enzyme histochemical studies. 287 24


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