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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
2
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pubmed:dateCreated |
1992-2-14
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pubmed:abstractText |
Regulation of Na+/H+ exchange by fetal bovine serum was studied in Caco-2 cells, an established cell line derived from a human colon carcinoma. Cells were grown as polarized monolayers on collagen-coated filters and intracellular pH measured fluorometrically with 2',7'-bis(2-carboxymethyl)-5,6-carboxyfluorescein. Na+/H+ exchange was reduced 64% when cells were deprived of serum for 4 h. In contrast to other cell types, readdition of serum for 10 min did not activate Na+/H+ exchange; however, readdition of serum for 4 h restored Na+/H+ exchange to control values. This long-term effect of serum on Na+/H+ exchange activity could not be explained by changes in intracellular buffering capacity or intracellular [Na+]. 4-h serum deprivation reduced the K(t) of the exchanger for external Na+ from 21 to 6 mM, and reduced the V(max) by 57%, but did not alter the IC50 for amiloride in the presence of 140 mM Na+. Inhibition of protein synthesis with cycloheximide (5 microM) did not alter the effect of serum removal or readdition on Na+/H+ exchange. Low temperature (13 degrees C) completely prevented the inhibition of Na+/H+ exchange caused by the removal of serum. In addition, once Na+/H+ exchange was inhibited by serum removal at 37 degrees C, maintaining cells at 13 degrees C also blocked the recovery of Na+/H+ exchange caused by serum readdition. Conversely, cytochalasin D (0.1-20 microM) blocked the reduction of Na+/H+ exchange which occurred due to 4-h serum deprivation, but did not block the restoration of Na+/H+ exchange when the cells were re-exposed to serum for a further 4 h. Colchicine (20 microM) did not alter the effect of serum removal or readdition. These data suggest that serum regulates Na+/H+ exchange activity by a posttranslational mechanism which is dependent on F-actin.
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pubmed:grant | |
pubmed:commentsCorrections | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Actins,
http://linkedlifedata.com/resource/pubmed/chemical/Amiloride,
http://linkedlifedata.com/resource/pubmed/chemical/Carrier Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Colchicine,
http://linkedlifedata.com/resource/pubmed/chemical/Cycloheximide,
http://linkedlifedata.com/resource/pubmed/chemical/Cytochalasin D,
http://linkedlifedata.com/resource/pubmed/chemical/Leucine,
http://linkedlifedata.com/resource/pubmed/chemical/Protein Synthesis Inhibitors,
http://linkedlifedata.com/resource/pubmed/chemical/Sodium-Hydrogen Antiporter
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pubmed:status |
MEDLINE
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pubmed:month |
Jan
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pubmed:issn |
0021-9258
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
15
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pubmed:volume |
267
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
956-62
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pubmed:dateRevised |
2007-11-14
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pubmed:meshHeading |
pubmed-meshheading:1309780-Actins,
pubmed-meshheading:1309780-Amiloride,
pubmed-meshheading:1309780-Blood,
pubmed-meshheading:1309780-Carrier Proteins,
pubmed-meshheading:1309780-Colchicine,
pubmed-meshheading:1309780-Cycloheximide,
pubmed-meshheading:1309780-Cytochalasin D,
pubmed-meshheading:1309780-Humans,
pubmed-meshheading:1309780-Hydrogen-Ion Concentration,
pubmed-meshheading:1309780-Kinetics,
pubmed-meshheading:1309780-Leucine,
pubmed-meshheading:1309780-Protein Synthesis Inhibitors,
pubmed-meshheading:1309780-Sodium-Hydrogen Antiporter,
pubmed-meshheading:1309780-Tumor Cells, Cultured
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pubmed:year |
1992
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pubmed:articleTitle |
Serum regulates Na+/H+ exchange in Caco-2 cells by a mechanism which is dependent on F-actin.
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pubmed:affiliation |
Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't
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