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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2000-8-16
pubmed:abstractText
The aim of this study was to characterize the transport of organic cations at the intestinal level, by studying the characteristics of the transport of 1-methyl-4-phenylpyridinium (MPP+) in Caco-2 cells. Transepithelial flux as well as cellular accumulation of [3H]MPP+ were quantitatively similar when substrate was applied from the basolateral or apical cell membrane. Verapamil (100 microM) and rhodamine123 (10 microM) significantly reduced [3H]MPP+ transepithelial flux in the apical-to-basolateral direction. When cells were grown on plastic supports, [3H]MPP+ was rapidly accumulated in the cells, both by saturable and nonsaturable mechanisms. The kinetic parameters of the saturable component were: Km: 449 microM and Vmax: 2,249 pmol per mg protein and 5 min. Uptake of [3H]MPP+ was metabolic energy-dependent and Na+-, pH- and potential-independent. It was inhibited by several organic cations (verapamil, rhodamine123, daunomycin, vinblastine, tetrabutylammonium and vecuronium) but not by others (tetraethylammonium and N-methylnicotinamide). Decynium22 and corticosterone inhibited [3H]MPP+ uptake into the cells. The P-glycoprotein antibody UIC2 (20 microg/ml) had no effect. In conclusion, [3H]MPP+ is efficiently transported by Caco-2 cells in both basolateral-to-apical (secretion) and apical-to-basolateral (absorption) directions. Absorption of [3H]MPP+ at the apical membrane seems to occur through a carrier-mediated mechanism belonging to the Amphiphilic Solute Facilitator (ASF) family of transporters, but distinct from the known members of this family.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0028-1298
pubmed:author
pubmed:issnType
Print
pubmed:volume
361
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
505-13
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Characterization of the transport of the organic cation [3H]MPP+ in human intestinal epithelial (Caco-2) cells.
pubmed:affiliation
Department of Biochemistry, Faculty of Medicine, Porto, Portugal. fatima_martel@hotmail.com
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't