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:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The rates of movement of Na+, Rb+, Cl- and HCO3- from plasma to endolymph were studied in the elasmobranch fish, Squalus acanthias, by use of the appropriate isotopes. Rb+ was used as a marker for K+. The half-times to equilibrium for Na+, Rb+ and Cl- were about 100 hours; for HCO3- it was 6 hours. The equilibrium ratios, endolymph/plasma, are Na+ 0.87, K+ 26, Cl- 1.37, HCO3- 1.47. Carbonic anhydrase inhibition decreased the rate of HCO3- accumulation, suggesting that the process is actually the formation of endolymphatic HCO3- from plasma or tissue CO2. Increase in plasma pCO2 elevates endolymph HCO3- concentration. The secretory tissue contains carbonic anhydrase and Na-K-ATPase. These and other data suggest that a dominant feature of endolymph chemistry may be HCO3- formation linked in some fashion with K+ transport, through rates catalyzed by these two enzymes.
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PMID:Rates of ion movement from plasma to endolymph in the dogfish. 23 17

Canine peripheral venous or suprarenal aortic injections of sodium or meglumine iothalamate produced a significant swing towards an alkaline urine only in individual dogs injected with meglumine salts. When mean values were compared for the sodium or meglumine groups as a whole, however, no significant differences could be established for pH change or induced diuresis. With both salts, ATPase inhibition could play a role in urinary electrolyte excretion. Carbonic anhydrase inhibition does not seem to play a significant role in urinary pH changes induced by contrast media.
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PMID:Contrast and electrolyte dynamics of the intravenous pyelogram. I. Urinary pH and volume changes in the canine I. V. P. 24 32

The distribution of two ion transport enzymes in the vestibular system was investigated immunocytochemically. Immunostaining demonstrated abundant Na+,K(+)-ATPase in the basolateral plasmalemma of all dark cells and of cuboidal (transitional) cells bordering maculae and planum semilunatum cells bordering cristae. Na+,K(+)-ATPase was also present in nerve terminals impinging on vestibular hair cells and around nerve fibers and ganglion cells. Na+,K(+)-ATPase containing cells with fine intertwining processes were found within the perilymphatic stroma beneath maculae and cristae. These cells and interspersed nerves form a distinct, highly cellular plate that lies under neurosensory epithelium selectively. The catalytic alpha subunit of Na+,K(+)-ATPase in vestibular epithelia differs antigenically from the alpha subunit in nerves and from the alpha subunit in salivary gland and renal epithelium. Carbonic anhydrase (CA) isozyme II was localized in the apex of all supporting cells in neurosensory epithelia. In contrast, CA II immunostaining varied in vestibular dark cells showing heterogeneity in ion transport activity among these cells. Immunostaining evidenced CA II also in perilymphatic stromal cells which were presumably fibroblastic in nature and which correspond in location with the Na+,K(+)-ATPase positive cells under the vestibular neurosensory epithelium.
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PMID:Immunolocalization of Na+,K(+)-ATPase and carbonic anhydrase in the gerbil's vestibular system. 169 Jan 98

Sarcolemmal vesicles of white and red skeletal muscles of the rabbit were prepared by consecutive density gradient centrifugations in sucrose and dextran according to Seiler and Fleischer (1982, J. Biol. Chem. 257, 13,862-13,871). White and red muscle membrane fractions enriched in sarcolemma were characterized by high ouabain-sensitive Na+, K(+)-ATPase, by high Mg2(+)-ATPase activity, and by a high cholesterol content. Ca2(+)-ATPase activity, a marker enzyme for sarcoplasmic reticulum, was not detectable in the highly purified white and red muscle sarcolemmal fractions. White and red muscle sarcolemmal fractions exhibited no significant differences with regard to Na+, K(+)-ATPase, Mg2(+)-ATPase, and cholesterol. Specific activity of carbonic anhydrase in white muscle sarcolemmal fractions was 38 U.ml/mg and was 17.6 U.ml/mg in red muscle sarcolemma. Inhibition properties of sarcolemmal carbonic anhydrase were analyzed for acetazolamide, chlorzolamide, and cyanate. White muscle sarcolemmal carbonic anhydrase is characterized by inhibition constants, KI, toward acetazolamide of 4.6 X 10(-8) M, toward chlorzolamide of 0.75 X 10(-8) M, and toward cyanate of 1.3 X 10(-4) M. Red muscle sarcolemmal carbonic anhydrase is characterized by KI values toward acetazolamide of 8.1 X 10(-8) M, toward chlorzolamide of 6.3 X 10(-8) M, and toward cyanate of 0.81 X 10(-4) M. In contrast to the high specific carbonic anhydrase activities in sarcolemma, carbonic anhydrase activity in sarcoplasmic reticulum from white muscle varied between values of only 0.7 and 3.3 U.ml/mg. Carbonic anhydrase of red muscle sarcoplasmic reticulum ranged from 2.4 to 3.7 U.ml/mg.
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PMID:Sarcolemmal carbonic anhydrase in red and white rabbit skeletal muscle. 211 70

Carbonic anhydrase (CA) and Mg2(+)-dependent ATPase and Mg2(+)-dependent, HCO3(-)-stimulated ATPase (Mg2(+)-HCO3(-)-ATPase) activities in rat duodenal mucosa and kidney cortex were examined with respect to thyroidal status. Administration of 50 and 150 micrograms thyroxine (T4)/kg per day s.c. for 7 days decreased duodenal cytosol CA activity to 66% of control with the former and 43% with the latter dose, while Mg2(+)-HCO3(-)-ATPase activity in brush borders of duodenal mucosa was increased to 116% of control by 150 micrograms T4/kg. CA and Mg2(+)-HCO3(-)-ATPase activities in the cytosol and brush border of kidney cortex did not change after administration of T4. Hypothyroidism induced by thyroidectomy for 2 and 4 weeks or administration of methimazole (2.5-20 mg/kg per day s.c. or peroral) for 2, 3 and 4 weeks all increased duodenal cytosol CA activity, to about 140% at 2 weeks and 153% at 4 weeks after thyroidectomy, and to about 136% after the oral administration of 10 mg methimazole/kg per day for 4 weeks, while brush border Mg2(+)-HCO3(-)-ATPase activity was decreased to 56% of control 4 weeks after thyroidectomy and to 74% after the s.c. administration of 20 mg methimazole/kg day for 3 weeks. The increase in CA activity and the decrease in ATPase activity after thyroidectomy were restored to normal levels by replacement with T4. Neither enzyme activity in the kidney changed in hypothyroidism. Serum concentrations of T4 and cortisol-like material increased after administration of T4, and serum concentrations of T4, aldosterone and cortisol-like material all decreased in hypothyroidism. Correlations were observed between duodenal CA and Mg2(+)-HCO3(-)-ATPase activities and serum concentrations of T4 (P less than 0.01). These results reveal that the decrease in CA activity and the increase in Mg2(+)-HCO3(-)-ATPase activity of duodenal mucosa in hyperthyroidism are reversed in hypothyroidism, while both enzyme activities in the kidney are unrelated to thyroidal status.
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PMID:Effects of hyper- and hypothyroidism on carbonic anhydrase, Mg2(+)-dependent ATPase and Mg2(+)-dependent, HCO3(-)-stimulated ATPase activities of rat duodenal mucosa and kidney cortex. 214 14

Pancreatic duct fragments were isolated from rat and hamster pancreas and were cultured in an agarose matrix for up to 8 weeks (rat) or 20 weeks (hamster). The fragments consisted predominantly of duct epithelium, lesser numbers of stromal and atrophied acinar cells, and small numbers of islet cells. Hamster ducts averaged 3 micrograms protein per duct while rat ducts averaged 1 microgram, and the protein:DNA ratio of both types of ducts was less than that of whole pancreas. Estimated average duct yields of 6% (hamster) and 1% (rat) were based on the protein content of the ducts. Duct viability was shown by the incorporation of 3H-thymidine and 3H-leucine into bulk DNA and protein and by autoradiography. gamma-Glutamyl transferase and (Na + K)-ATPase specific activities were slightly elevated while amylase was depressed in the ducts when compared with whole pancreas in both species. gamma-Glutamyl transferase was localized histochemically in both duct epithelium and in surviving acinar tissue, as seen in vivo. Amylase was shown by immunohistochemistry to be present within duct lumina and in atrophied acini and their lumina. Alkaline phosphatase and Mg-ATPase specific activities were elevated in the hamster, but reduced in the rat, when compared with whole pancreas. Hamster alkaline phosphatase and Mg-ATPase were localized by histochemistry to the duct stroma, where these enzymes are not detected in vivo. Carbonic anhydrase was found in the duct epithelium of both species, as in vivo, as well as in the duct stroma, unlike in vivo. Acid glycosaminoglycans, as revealed by alcian blue staining, were found at the apical surfaces and in the lumina of both kinds of ducts. Glutathione-S-transferase and glucose-6-phosphate dehydrogenase were elevated in rat ducts, but not in hamster ducts. The polypeptide compositions of cultured ducts, freshly isolated pancreatic islets, and whole pancreas were compared by one-dimensional sodium dodecyl sulfate polyacrylamide gradient gel electrophoresis. No duct-specific polypeptides were observed; the ducts were characterized mainly by the reduction or absence of polypeptides, including some zymogens, seen in whole pancreas.
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PMID:Biochemical and histochemical characterization of cultured rat and hamster pancreatic ducts. 244 50

The localization of carbonic anhydrase by histochemistry, of Na-K-ATPase by immunocytochemistry and of rod-shaped intramembranous particles by freeze-fracture electron microscopy, was determined in the collecting duct of rabbits. In the cortical collecting duct (CCD), rod-shaped particles, which are abundant in intercalated cells were observed in both the apical and basolateral membrane of all intercalated cells examined. In the outer stripe of the outer medullary collecting duct (OMCDo) a high density of rod-shaped particles was found only in the apical membrane of intercalated cells. All cells of the inner stripe of the outer medullary collecting duct (OMCDi) had rod-shaped particles in the apical membrane but not in the basolateral membrane. As the collecting duct entered the inner medulla the density of rod-shaped particles decreased until they were virtually absent in the terminal segment. Na-K-ATPase, localized to the basolateral membrane, was more abundant in principal cells than in intercalated cells in the CCD. In the OMCDo, staining was equal in principal and intercalated cells. All cells of the OMCDi and the inner medullary collecting duct (IMCD) stained for Na-K-ATPase. Carbonic anhydrase in the CCD was localized to the cell membranes and cytoplasm of intercalated cells. Principal cells did not stain for carbonic anhydrase. A similar pattern was seen in the OMCDo. In the outer region of the OMCDi most cells did not stain for carbonic anhydrase, whereas in the inner region the apical and lateral membranes of all cells stained for carbonic anhydrase. Weak cytoplasmic staining was occasionally seen. A similar pattern was seen in the initial half of the IMCD, while the terminal half of the IMCD did not stain. In this study, the localization of enzymes and rod-shaped intramembranous particles associated with Na+, K+, and H+ transport shows both segmental and cellular heterogeneity, and correlates with the known transport properties of tubule segments. The distribution of these enzymes and rod-shaped intramembranous particles is different in rabbits and rats, and may explain some of the functional differences between homologous segments in these species.
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PMID:Morphological heterogeneity of the rabbit collecting duct. 246 75

Turtle urinary bladder possesses four ion transport processes: Na+ absorption, H+ secretion, and HCO3- secretion-Cl- absorption. Each transport process is performed by a specific epithelial cell type. Granular cells absorb Na+ but they are not sensitive to antidiuretic hormone (ADH), unlike toad bladder granular cells. alpha-Carbonic anhydrase-rich (CA) cells secrete H+ via an apical H+-adenosinetriphosphatase (ATPase). Under conditions of low CO2 tension, this active pump is contained in the limiting membranes of certain cytoplasmic vesicles. The vesicles fuse with the apical membrane, and H+ pumps are incorporated into that membrane, as physiological conditions demand increased H+ secretion. The stimulus for fusion of these vesicles with the apical membrane appears to be intracellular acidification. beta-CA cells secrete HCO3- and reabsorb Cl-, both processes driven by H+-ATPase in the basolateral membrane in series with an apical Cl- -HCO3- exchanger. Increased intracellular adenosine 3',5'-cyclic monophosphate concentration in beta-cells stimulates net HCO3- secretion and induces an electrogenic component of this flux by activating an apical Cl- channel. This activation accompanies the fusion of an intracellular tubulovesicular network with the apical membrane. The membrane of this network may contain Cl- channels.
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PMID:Turtle urinary bladder: regulation of ion transport by dynamic changes in plasma membrane area. 251 70

Highly specific antibodies against vital enzymes of the collecting ducts were used to study the appearance of cell type specific enzyme profiles in developing rat kidneys. (Na+K)-ATPase, the abundant enzyme of principal cells, could be detected early in utero in most collecting duct cells. However, the characteristic basolateral polarization of this enzyme did not appear until the first hours after birth. After this, the relative amount of (Na+K)-ATPase immunoreactive cells along collecting ducts decreased steadily, to reach the amount found in adult rat kidneys by the 30th postnatal day. Carbonic anhydrase immunoreactivity characteristic for intercalated cells was not detectable in fetal kidneys, but appeared soon after birth, with steadily increasing numbers of cells that were positive. Interestingly, immunoreactive band 3 glycoprotein (anion channel protein of erythrocytes) did not appear until the 5th day of life, with only a slowly increasing number of cells positive for this probe. These results, showing the sequential appearance of cell type-specific enzyme reactivities along collecting ducts, likely reflect a similar pattern of functional development of the respective main cell types. These results may provide an explanation for physiologic neonatal acidosis, as the enzyme profile associated with proton secretion was seen to appear slowly during the first weeks of life in a distinct manner.
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PMID:Ontogeny of cell type-specific enzyme reactivities in kidney collecting ducts. 282 8

1. Plasma sodium and chloride levels were determined in goldfish, Carassius auratus L., following acclimation to 5, 15, 25 and 35 degrees C. Carbonic anhydrase and (Na+/K+)-stimulated ATPase activities of gill and kidney were also assayed at both acclimation temperature and 41 degrees C. 2. Consistent with earlier findings this eurythermal species exhibits more variation in plasma composition with temperature than do the more stenothermal salmonids. Seasonal changes were also observed. 3. Despite differences in detail the overall pattern of transport enzyme activity change with acclimation was comparable to that previously observed in trout. The goldfish is, however, notable for high levels of renal carbonic anhydrase activity, and presumably employs this system more than does the trout to drive urinary recovery of ions by H+:Na+ and HCO3-:Cl- exchanges.
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PMID:Branchial and renal (Na+/K+) ATPase and carbonic anhydrase activities in a eurythermal freshwater teleost, Carassius auratus L. 612 44


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