Document Detail

Sodium/proton exchange in the maintenance of intracellular pH in FRTL-5 thyroid cells.
MedLine Citation:
PMID:  2843345     Owner:  NLM     Status:  MEDLINE    
In the present study we describe a Na+/H+ exchange system in FRTL-5 rat thyroid cells and its role in the regulation of intracellular pH (pHi). The pHi of these cells was measured in acidic medium (pH 6.5) using the equilibrium distribution of 14C-labeled 5,5'-dimethyl-oxazolidine-2,4-dione. The estimated pHi in 10 separate experiments was 7.30 +/- 0.01 (mean +/- SE). The pHi declined to 6.87 +/- 0.02 when equimolar concentrations of choline+ replaced Na+ in the incubation medium, but was restored when cells were placed in a medium containing 50 mM Na+. The necessity for external Na+ to maintain pHi, when cells are exposed to acidic solutions, is consistent with a Na+/H+ antiport system in these cells. This is further supported by the observation that pHi decreased to 6.70 +/- 0.01 when amiloride, an inhibitor of Na+/H+ exchange, was added, and that this agent prevented the recovery of pHi in Na+-depleted cells after addition of Na+ to the medium. This report also provides additional information concerning the relationship between H+ and I- uptake and suggests that there are two I- transport systems: one that is Na+-dependent, 4,4'-diisothiocyano 2,2'-disulfonic acid stilbene-sensitive, and not associated with intracellular acidification, and the other operative at an external pH of 6.5 and associated with intracellular acidification.
C Marcocci; E F Grollman
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Endocrinology     Volume:  123     ISSN:  0013-7227     ISO Abbreviation:  Endocrinology     Publication Date:  1988 Oct 
Date Detail:
Created Date:  1988-10-27     Completed Date:  1988-10-27     Revised Date:  2003-11-14    
Medline Journal Info:
Nlm Unique ID:  0375040     Medline TA:  Endocrinology     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1705-11     Citation Subset:  AIM; IM    
Section on Cell Regulation, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892.
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MeSH Terms
4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid
4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / analogs & derivatives,  pharmacology
Amiloride / pharmacology
Carrier Proteins / metabolism*
Cell Line
Culture Media
Hydrogen-Ion Concentration
Iodides / metabolism
Sodium-Hydrogen Antiporter
Thyroid Gland / metabolism*
Reg. No./Substance:
0/Carrier Proteins; 0/Cations; 0/Culture Media; 0/Iodides; 0/Sodium-Hydrogen Antiporter; 2609-46-3/Amiloride; 27816-59-7/4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; 53005-05-3/4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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