Document Detail

Activity and density of the Na+/H+ antiporter in normal and transformed human lymphocytes and fibroblasts.
MedLine Citation:
PMID:  7943203     Owner:  NLM     Status:  MEDLINE    
The turnover number for the sodium-hydrogen exchanger isoform 1 (NHE-1) has been determined in human lymphocytes and MRC5 fibroblasts and in their virally transformed counterparts. Using fluorometric methods, we have determined the intracellular pH and Na+/H+ antiport activity of these cells. Intracellular pH was elevated in both lines of transformed cells. In contrast, Na+/H+ antiport activity was apparently unchanged in simian virus 40-transformed MRC5 fibroblasts (MRC5 SV1 TV1 28.9 +/- 5.2 mM/min compared with MRC5 fibroblasts 26.5 +/- 5.3 mM/min) but slightly increased in Epstein-Barr virus-transformed lymphoblasts (16.7 +/- 1.0 mM/min compared with lymphocytes 13.5 +/- 2.3 mM/min, P < 0.05). With the use of specific antisera to NHE-1, viral transformation was associated with a decreased number of NHE-1 molecules per cell in fibroblasts (from 441,504 +/- 53,428 to 64,745 +/- 7,151 sites/cell, P < 0.001) but an increased number in lymphocytes (from 14,066 +/- 3,100 to 22,474 +/- 4,050 sites/cell, P < 0.01). The NHE-1 density per cell yielded very similar turnover numbers for NHE-1 in the untransformed cells (lymphocytes, 3,161 +/- 833 cycles/s; MRC5 fibroblasts, 3,026 +/- 441 cycles/s), which were significantly elevated in the transformed cells (lymphoblasts, 8,471 +/- 1,177 cycles/s; MRC5 SV1 TV1, 10,521 +/- 2,299 cycles/s, P < 0.001 compared with untransformed cells). We conclude that viral transformation has different effects on Na+/H+ antiport activity and NHE-1 density per cell in different cell types, but the turnover number of NHE-1 is significantly increased after viral transformation, which correlates with the increased proliferation rate of these transformed cells.
M Siczkowski; J E Davies; L L Ng
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The American journal of physiology     Volume:  267     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1994 Sep 
Date Detail:
Created Date:  1994-10-24     Completed Date:  1994-10-24     Revised Date:  2009-09-29    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  C745-52     Citation Subset:  IM    
Department of Pharmacology, Leicester Royal Infirmary, United Kingdom.
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MeSH Terms
Cell Line
Cell Transformation, Viral*
Fibroblasts / metabolism*
Hydrogen-Ion Concentration
Intracellular Membranes / metabolism
Lymphocytes / metabolism*
Reference Values
Sodium-Hydrogen Antiporter / metabolism*
Grant Support
//Wellcome Trust
Reg. No./Substance:
0/Sodium-Hydrogen Antiporter

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