AJP - Regu Information on EB 2010
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Regul Integr Comp Physiol 293: R538-R547, 2007. First published May 2, 2007; doi:10.1152/ajpregu.00906.2006
0363-6119/07 $8.00
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
293/1/R538    most recent
00906.2006v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via Web of Science (2)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Pinho, M. J.
Right arrow Articles by Soares-da-Silva, P.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Pinho, M. J.
Right arrow Articles by Soares-da-Silva, P.

WATER AND ELECTROLYTE HOMEOSTASIS

Underexpression of the Na+-dependent neutral amino acid transporter ASCT2 in the spontaneously hypertensive rat kidney

Maria João Pinho,1 Vanda Pinto,1 Maria Paula Serrão,1 Pedro A. Jose,2 and Patrício Soares-da-Silva1

1Institute of Pharmacology and Therapeutics, Faculty of Medicine, Porto, Portugal; and 2Department of Pediatrics, Georgetown University, Washington, District of Columbia

Submitted 28 December 2006 ; accepted in final form 17 April 2007

This study examined the inward transport of L-[14C]alanine, an ASCT2 preferential substrate, in monolayers of immortalized renal proximal tubular epithelial (PTE) cells from Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rats. The expression of ASCT2 in WKY and SHR PTE cells and kidney cortices from WKY and SHR was also evaluated. L-[14C]alanine uptake was highly dependent on extracellular Na+. Replacement of NaCl by LiCl or choline chloride abolished transport activity in SHR and WKY PTE cells. In the presence of the system L inhibitor BCH, Na+-dependent L-alanine uptake in WKY and SHR PTE cells was inhibited by alanine, serine, and cysteine, which is consistent with amino acid transport through ASCT2. The saturable component of Na+-dependent L-alanine transport under Vmax conditions in SHR PTE cells was one-half of that in WKY PTE cells, with similar Km values. Differences in magnitude of Na+-dependent L-alanine uptake through ASCT2 between WKY and SHR PTE cells correlated positively with differences in ASCT2 protein expression, this being more abundant in WKY PTE cells. Abundance of ASCT2 transcript and protein in kidney cortices of SHR rats was also lower than that in normotensive WKY rats. In conclusion, immortalized SHR and WKY PTE cells take up L-alanine mainly through a high-affinity Na+-dependent amino acid transporter, with functional features of ASCT2 transport. The activity and expression of the ASCT2 transporter were considerably lower in the SHR cells.

L-alanine transport; hypertension; alanine-serine-cysteine-threonine transporter-2


Address for reprint requests and other correspondence: P. Soares-da-Silva, Institute of Pharmacology and Therapeutics, Faculty of Medicine, 4200 Porto, Portugal (e-mail: pss{at}med.up.pt)






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online
Copyright © 2007 by the American Physiological Society.