Linked Life Data

9632674

Source:http://linkedlifedata.com/resource/pubmed/id/9632674

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
26
pubmed:dateCreated
1998-8-3
pubmed:abstractText
oatp1 is an hepatic sinusoidal organic anion transporter that mediates uptake of various structurally unrelated organic compounds from blood. The driving force for uptake on oatp1 has not been identified, although a role for bicarbonate has recently been proposed. The present study examined whether oatp1-mediated uptake is energized by efflux (countertransport) of intracellular reduced glutathione (GSH), and whether hydrophobic glutathione S-conjugates such as leukotriene C4 (LTC4) and S-dinitrophenyl glutathione (DNP-SG) form a novel class of substrates for oatp1. Xenopus laevis oocytes injected with the complementary RNA for oapt1 demonstrated higher uptake of 10 nM [3H]LTC4 and 50 microM [3H]DNP-SG, and higher efflux of [3H]GSH (2.5 mM endogenous intracellular GSH concentration). The oatp1-stimulated LTC4 and DNP-SG uptake was independent of the Na+ gradient, cis-inhibited by known substrates of this transport protein and by 1 mM GSH, and was saturable, with apparent Km values of 0.27 +/- 0.06 and 408 +/- 95 microM, respectively. Uptake of [3H]taurocholate, an endogenous substrate of oatp1, was competitively inhibited by DNP-SG. Of significance, oatp1-mediated taurocholate and LTC4 uptake was cis-inhibited and trans-stimulated by GSH, and [3H]GSH efflux was enhanced in the presence of extracellular taurocholate or sulfobromophthalein, indicating that GSH efflux down its large electrochemical gradient provides the driving force for uptake via oatp1. The stoichiometry of GSH/taurocholate exchange was 1:1. These findings identify a new class of substrates for oatp1 and provide evidence for GSH-dependent oatp1-mediated substrate transport.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
26
pubmed:volume
273
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
16184-91
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Identification of glutathione as a driving force and leukotriene C4 as a substrate for oatp1, the hepatic sinusoidal organic solute transporter.
pubmed:affiliation
Department of Environmental Medicine, University of Rochester School of Medicine, Rochester, New York 14642, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't