Linked Life Data

10421658

Source:http://linkedlifedata.com/resource/pubmed/id/10421658

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1999-8-12
pubmed:abstractText
The secretion of bilirubin conjugates from hepatocytes into bile represents a decisive step in the prevention of hyperbilirubinemia. The bilirubin conjugates, monoglucuronosyl bilirubin (MGB) and bisglucuronosyl bilirubin (BGB), were previously suggested to be endogenous substrates for the apical multidrug resistance protein (MRP2), a member of the adenosine triphosphate (ATP)-binding cassette family of transporters (symbol ABCC2), also termed canalicular multispecific organic anion transporter. We have characterized this ATP-dependent transport using membrane vesicles from human embryonic kidney (HEK) cells expressing recombinant rat as well as human MRP2. MGB and BGB, (3)H-labeled in the glucuronosyl moiety, were synthesized enzymatically with recombinant UDP-glucuronosyltransferase 1A1, and stabilized with ascorbate. Rates for ATP-dependent transport of MGB and BGB (0.5 micromol/L each) by human MRP2 were 183 and 104 pmol x mg protein(-1) x min(-1), respectively. K(m) values were 0.7 and 0.9 micromol/L for human MRP2, and 0.8 and 0.5 micromol/L for rat MRP2, with MGB and BGB as substrates, respectively. Leukotriene C(4) and 17beta-glucuronosyl estradiol, which are both known high-affinity substrates for human MRP2, inhibited [(3)H]MGB transport with IC(50) values of 2.3 and 30 micromol/L, respectively. Cyclosporin A competitively inhibited human and rat MRP2-mediated transport of [(3)H]MGB, with K(i) values of 21 and 10 micromol/L, respectively. Our results provide direct evidence that recombinant MRP2, cloned from rat as well as human liver, mediates the primary-active ATP-dependent transport of the bilirubin conjugates MGB and BGB.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0270-9139
pubmed:author
pubmed:issnType
Print
pubmed:volume
30
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
485-90
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Transport of monoglucuronosyl and bisglucuronosyl bilirubin by recombinant human and rat multidrug resistance protein 2.
pubmed:affiliation
Division of Tumor Biochemistry, Deutsches Krebsforschungszentrum, Heidelberg, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't