Document Detail

Regulatory volume decrease after swelling induced by urea in fibroblasts: prominent role of organic osmolytes.
MedLine Citation:
PMID:  17684706     Owner:  NLM     Status:  MEDLINE    
Cell swelling, regulatory volume decrease (RVD), volume-sensitive Cl(-) (Cl(-) (swell)) current and taurine efflux after exposure to high concentrations of urea were characterized in fibroblasts Swiss 3T3, and results compared to those elicited by hyposmotic (30%) swelling. Urea 70, 100, and 150 mM linearly increased cell volume (8.25%, 10.6%, and 15.7%), by a phloretin-inhibitable process. This was followed by RVD by which cells exposed to 70, 100, or 150 mM urea recovered 27.6%, 38.95, and 74.1% of their original volume, respectively. Hyposmolarity (30%) led to a volume increase of 25.9% and recovered volume in 32.5%. (3)H-taurine efflux was increased by urea with a sigmoid pattern, as 9.5%, 18.9%, 71.5%, and 89% of the labeled taurine pool was released by 70, 100, 150, or 200 mM urea, respectively. Only about 11% of taurine was released by 30% hyposmolarity reduction in spite of the high increase in cell volume. Urea-induced taurine efflux was suppressed by NPPB (100 microM) and markedly reduced by the tyrosine kinase-general blocker AG18. The Cl(-) (swell) current was more rapidly activated and higher in amplitude in the hyposmotic than in the isosmotic/urea condition (urea 150 mM), but this was not sufficient to accomplish an efficient RVD. These results showed that at similar volume increase, cells swollen by urea showed higher taurine efflux, lower Cl(-) (swell) current and more efficient RVD, than in those swollen by hyposmolarity. The correlation found between RVD efficiency and taurine efflux suggest a prominent role for organic over ionic osmolytes for RVD evoked by urea in isosmotic conditions.
Alejandra López-Domínguez; Gerardo Ramos-Mandujano; Erika Vázquez-Juárez; Herminia Pasantes-Morales
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2007-08-08
Journal Detail:
Title:  Molecular and cellular biochemistry     Volume:  306     ISSN:  0300-8177     ISO Abbreviation:  Mol. Cell. Biochem.     Publication Date:  2007 Dec 
Date Detail:
Created Date:  2007-10-22     Completed Date:  2008-01-29     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0364456     Medline TA:  Mol Cell Biochem     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  95-104     Citation Subset:  IM    
Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad Universitaria, Circuito Exterior, Mexico, DF 04510, Mexico.
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MeSH Terms
Aspartic Acid / metabolism
Cell Size / drug effects*
Chlorides / metabolism
Fibroblasts / drug effects*
Nitrobenzoates / metabolism
Osmolar Concentration
Swiss 3T3 Cells
Taurine / metabolism
Urea / pharmacology*
Reg. No./Substance:
0/Chlorides; 0/Nitrobenzoates; 107-35-7/Taurine; 107254-86-4/5-nitro-2-(3-phenylpropylamino)benzoic acid; 56-84-8/Aspartic Acid; 57-13-6/Urea

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

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