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:3.1.3.1 (alkaline phosphatase)
47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

As enterocytes migrate from crypts to villi they differentiate and mature. To examine the effect of epithelial differentiation on ion transport we studied 22Na+ efflux and (Na+--K+)-adenosine triphosphatase activity in suspensions of epithelial cells selectively isolated from different regions of the villus to compare crypt cells with villous tip cells. Enterocytes were isolated from rat jejunum by a dilation-vibration technique. Thymidine kinase, sucrase, and alkaline phosphatase activities were measured as markers of specific cell populations. Compared to villous cells, cells from the crypt region demonstrated lower (Na"--K+)-adenosine triphosphatase activity, lower total and passive Na+ efflux rate constants, and failure of Na+ transport to respond to an actively transported nonelectrolyte.
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PMID:Na+ transport in jejunal crypt cells. 13 28

To determine whether choleretic infusions of bile acids modified the function or structure of the membrane of the bile canaliculus, sodium taurocholate (NaTc) or dehydrocholate (DHC) was infused into male rats at a rate of 80 mumoles per hour over an 18-hour period. Bile was collected by fistula and phospholipid and cholesterol content was measured in bile, liver homogenates, and isolated liver plasma membranes (LPM) enriched in bile canaliculi. Na+, K+-ATPase, Mg2+-ATPase, 5'-nucleotidase, and alkaline phosphatase activities were also measured in LPM. NaTc infusions enhanced cholesterol and phospholipid output in the bile in association with a significant increase in phospholipid in both LPM and liver homogenate. Although DHC infusions resulted in a comparable excretion of bile acid, phospholipid and cholesterol output in bile did not increase from control values and the concentration of these lipids in LPM and liver homogenate also did not change. However, LPM Na+, K+-ATPase significantly increased after DHC infusions compared to NaTc-infused animals or controls. Neither bile acid altered the activities of Mg2+-ATPase, 5'-nucleotidase, or alkaline phosphatase. Both bile acids increased the diameter of the lumen of the bile canaliculus as assessed by scanning electron microscopy and produced irregularities and outpouchings in the canalicular membrane. Diverticuli and loss of microvilli were most prominent with DHC infusions whereas canalicular side branching and the density of microvilli, either remained unchanged or increased following NaTc infusions. Although the morphologic findings are qualitative, the results of these studies indicate that chronic choleretic infusions of NaTc and DHC have divergent effects, not only on enzyme activities in liver plasma membrane, but on phospholipid composition and 3-dimensional structure. These findings suggest that bile acids may after biliary secretion not only through their osmotic effects, but by modifying lipids and enzymes in the membrane of the bile canaliculus.
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PMID:Effects of chronic choleretic infusions of bile acids on the membrane of the bile canaliculus. A biochemical and morphologic study. 13 67

Changes in activities of plasma membrane enzymes during liver regeneration may be related to the maintenance of hepatic function or to the regulation of cell proliferation. Plasma membranes were isolated from rat livers at various times after partial hepatectomy, and the specific activities of alkaline phosphatase, (Na+ + K+)-ATPase, leucine aminopeptidase, 5'-nucleotidase, and adenylate cyclase (basal and with glucagon or epinephrine) were measured. Alkaline phosphatase and (Na+ + K+)-ATPase activity increased 3.6-fold and 2-fold respectively, during the first 48 h after partial hepatectomy. The time of onset and duration of change suggest that these increases in activity are involved in the maintenance of bile secretion. Decreases in leucine aminopeptidase activity at 48--108 h and in 5'-nucleotidase activity at 12--24 h were observed, which may be involved in the restoration of protein and accumulation of RNA. The basal activity of adenylate cyclase increased after partial hepatectomy. The response of adenylate cyclase to epinephrine showed a transitory increase between 36 and 108 h after surgery, while the response to glucagon was decreased by approximately 50% at all time points through 324 h after surgery. These changes in the hormone responsiveness of adenylate cyclase are similar to those previously observed in fetal and preneoplastic liver.
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PMID:Changes in plasma membrane enzyme activities during liver regeneration in the rat. 14 24

The intracellular localization of anion-sensitive Mg2+-ATPase in rat pancreas was studied by differential centrifugation, density gradient centrifugation and by the use of inhibitors of mitochondrial Mg2+-ATPase. The anion-sensitive MG2+-ATPase appears to be localized almost exclusively in a mitochondrial (15 min, 15 000 times g) fraction which shows two peaks after density gradient centrifugation. Both peaks coincide with the highest levels of cytochrome c oxidase activity, but not with alkaline phosphatase, (Na+ plus K+)-ATPase and leucine aminopeptidase activities or RNA. They appear to be equal sensitive to inhibition by oligomycin, aurovertin D and the rat liver mitochondrial inhibitor protein, at least when 1 mM EDTA is present in the isolation media. We conclude that no significant plasma membrane-located anion-sensitive Mg2+-ATPase activity is present in rat pancreas.
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PMID:Is there a plasma membrane-located anion-sensitive ATPase? IV. Distribution of the enzyme in rat pancreas. 15 25

On the basis of electron microscopic evidence, a preparation of microvilli obtained from the surfaces of placental villi was previously considered by us to represent syncytiotrophoplast plasma membrane. The present investigation was undertaken to obtain independent biochemical evidence on the nature of the preparation. Protein, lipid, carbohydrate, sialic acid, phospholipid and cholesterol concentration were determined and found to be consistent with analyses of membranes obtained from other sources. Enzyme membrane markers (5'-nucleotidase, (Na+ + K+)-ATPase and alkaline phosphatase) were also assayed, and found to be considerably enriched in the microvillous preparation compared to the whole placental homogenate. These findings, together with other evidence, support the contention that the preparation is indeed syncytiotrophoblast plasma membrane.
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PMID:Preparation and characterization of human syncytiotrophoblast plasma membrane. 15 76

A prospective study was carried out in 25 patients following visceral angiography using, on average, 3.5 (2.3 to 4.3) ml/kg. of sodium methyl glucamine diatrizoate 76%. No significant changes were found in the liver enzymes (SGTP, LDH and alkaline phosphatase). On the other hand, there was a significant but temporary rise of serum creatinine from 0.9 +/- 0.2 mg% to 1.2 +/- 0.3 mg% as well as transient proteinuria (7 cases) and microhaematuria (6 cases). With the usual contrast doses for visceral angiography, the kidney appears to be the critical organ. In order to reduce the risks of renal complications, contrast doses should be kept to below 4 ml/kg. if possible; angiography should be carried out only if the patient is well hydrated and the indications for angiography should be particularly stringent if there is previous renal damage.
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PMID:[Evaluation of hepatic and renal function after visceral angiography (author's transl)]. 15 51

Using the modified model of Masugi's nephritis in rats, the antinephritic effects of sodium chondroitin sulfate (CS) and other drugs were evaluated by determining the biochemical parameters in urine, serum and renal cortex as well as light microscopic observation in kidneys by preventive and curative tests. In the preventive test where drug treatment was initiated at the same time as the injection of anti-kidney serum, CS (200 mg/kg p.o.) was effective in reducing serum triglyceride level, but was ineffective against other parameters. In the curative test where drug treatment was given from the 10th day after the induction of nephritis, CS (200 mg/kg p.o.) resulted in reductions of urinary excretions of protein and enzymes such as alkaline phosphatase and N-acetyl-beta-glucosaminidase, the inhibition of urinary fibrinolytic activity and reduction in levels of serum cholesterol and triglyceride. Moreover, histological examination indicated a significant reduction of the index of glomerular lesions by the treatment of this drug. Of other drugs, dexamethasone (0.1 mg/kg p.o.) was effective in both tests, while warfarin potassium (0.05 or 0.1 mg/kg p.o.) exerted a beneficial effect only in the preventive test. From these results, the effectiveness of CS in the curative test is probably due to promotion of healing of damaged tissue in the kidneys.
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PMID:[Pharmacological studies on experimental nephritic rats (6). Antinephritic effects of sodium chondroitin sulfate and other drugs on modified type of Masugi's nephritis]. 16 45

The formation of cellular aggregates (foci) in CV-1 cells following infection with Yaba tumor poxvirus is dependent upon cell passage level, temperatue of incubation, and calcium concentration in the medium. Resistance of older cells can be reversed by maintaining calcium at 0.1 mM or by adding cortisone acetate (1 mug/ml), hydrocortisone, or estradiol-17beta to the cultures. In susceptible cells, foci formation was inhibited slightly by methyltestosterone and inhibited completely by dexamethasone, aldosterone and progesterone. Activities and patterns of enzymes associated with cytoplasmic membranes (alkaline phosphatase, mononucleotidase, and Na+-K+-adenosine triphosphatase) and lysosomes (beta-glucuronidase and acid phosphatase) of the younger susceptible and the older resistant CV-1 cells differed. These differences apparently occurred in concert with phenotypic changes in the membranes that reduced the mobility of older resistant cells. In susceptible culture, unifected cells migrated to the infected cell and participated in foci formation. Reduction of the calcium content to 0.1 mM apparently removed some of the constraints on mobility of the resistant cells. Although the hormones may have had a similar effect, the changes in enzyme patterns indicated basic alterations in protein synthesis. The development of resistance to foci formation occurred between the 45th and 50th passage level. Hormonal reversal of this resistance resulted in enzyme profiles that reflected the pattern of young susceptible cells.
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PMID:Alterations of enzymes associated with plasma membranes and cellular organelles during infection of CV-1 cells with Yaba tumor poxvirus. 16 62

The disruption of the molecular organization of the plasma membrane of leukocytes by phagocytosable particles, or by agents such as surfactants, antibodies, phospholipase C, fatty acids and chemotactic factors, leads to a stimulation of the phagocyte oxidative metabolism. Concanavalin A (Con A) has been used as a tool to study the mechanism of this metabolic regulation. The binding of Con A to the surface of polymorphonuclear leukocytes (PMNL) or macrophages produces a rapid enhancement of oxygen uptake and glucose oxidation through the hexose monophosphate pathway (HMP). This is explained by an activation of the granular NADPH oxidase, the key enzyme in the metabolic stimulation. The effect of Con A is not due to endocytosed lectin, since Con A covalently coupled to large sepharose beads still acts as stimulant. The metabolic changes caused by Con A are reversible. If, after the onset of stimulation, sugars with high affinity for Con A are added to the leukocyte suspension, the activity of granular NADPH oxidase and the rate of respiration and glucose oxidation return to their resting values. The metabolic burst, while partially supressed by treatment of PMNL with iodoacetate, sodium flouride and cytochalasin B, is slightly increased by colchicine. Con A induces a selective release of granular enzymes (beta-glucuronidase, peroxidase, alkaline phosphatase) from PMNL, whereas no leakage of cytoplasmic enzymes is observed. The enzyme release is inhibited by iodoacetate and by drugs known to increase cell levels of cyclic AMP. Based on a current view of the mode of interaction between Con A and cell surfaces, a model of the metabolic disruption of leukocytes is presented.
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PMID:Concanavalin A as a probe for studying the mechanism of metabolic stimulation of leukocytes. 16 45

The hydrolysis of disodium p-nitrophenyl phosphate at pH 9.0 by slices of formaldehydee-fixed rat renal cortex was investigated by colorimetric estimation of the nitrophenol liberated. It was found that three types of activity could be identified on the basis of their responses to inhibitors and cations: (a) alkaline phosphatase sensitive to inhibition by L-tetramisole; (b) potassium-dependent phosphatase, probably identifiable with the phosphatase component of sodium-potassium-dependent transport adenosine triphosphatase (?Na-K-ATPase); and (c) alkaline phosphatase insensitive to L-tetramisole. It was found that in the presence of strontium ions, as used in Na-K-ATPase cytochemistry, the activities of the second and third types of enzyme were approximately equal. The implications of these findings for the cytochemical demonstration of Na-K-ATPase are discussed.
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PMID:The significance of inhibitor-resistant alkaline phosphatase in the cytochemical demonstration of transport adenosine triphosphatase. 16 3


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