title: ATP-dependent transport of organic anions into isolated basolateral membrane vesicles from rat intestine.
abstract: The mechanism for the cellular extrusion of organic anions across the intestinal basolateral membrane was examined using isolated membrane vesicles from rat jejunum, ileum, and colon. It was found that 17beta-estradiol 17beta-D-glucuronide (E217betaG) is taken up in an ATP-dependent manner into the basolateral membrane vesicles (BLMVs) but not into the brush-border or microsomal counterparts. The ATP-dependent uptake of E217betaG into BLMVs from jejunum and ileum was described by a single component with a Km value of 23.5 and 8.31 microM, respectively, whereas that into the BLMVs from colon was described by assuming the presence of high (Km=0.82 microM)- and low-affinity (Km=35.4 microM) components. Taurocholate, 6-hydroxy-5,7-dimethyl-2-methylamino-4-(3-pyridylmethyl) benzothiazole glucuronide and taurolithocholate sulfate, but not leukotriene C4, were significantly taken up by the BLMVs. In addition to such substrate specificity, the inhibitor sensitivity of the ATP-dependent transport in BLMVs was similar to that of rat multidrug resistance-associated protein 3 (Mrp3), which is located on the basolateral membrane of enterocytes. Together with the fact that the rank order of the extent of the expression of Mrp3 (jejunum < ileum << colon) is in parallel with that of the extent of the transport of ligands, these results suggest that the ATP-dependent uptake of organic anions into isolated intestinal BLMVs is at least partly mediated by Mrp3.
authors.affiliation: Dept. of Molecular Pharmacokinetics, Graduate School of Pharmaceutical Sciences, The Univ. of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Shoji
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Suzuki
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kusuhara
authors.forename: Yuka
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Shingo
authors.initials: S
authors.lastname: Sakamoto
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Sugiyama
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D001647:Bile Acids and Salts / Q000378:metabolism; D001692:Biological Transport / Q000502:physiology; D015415:Biomarkers; D002462:Cell Membrane / Q000378:metabolism; D016764:Cell Polarity / Q000502:physiology*; D004847:Epithelial Cells / Q000166:cytology* / Q000378:metabolism*; D004958:Estradiol / Q000031:analogs & derivatives / Q000493:pharmacokinetics; D007413:Intestinal Mucosa / Q000166:cytology / Q000378:metabolism; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000378:metabolism; D027361:Organic Anion Transporters / Q000378:metabolism*; D051381:Rats; D014316:Tritium
chemical_list: D000255:Adenosine Triphosphate; D001647:Bile Acids and Salts; D015415:Biomarkers; D004958:Estradiol; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D027361:Organic Anion Transporters; D014316:Tritium; C025483:estradiol-17 beta-glucuronide; C114462:multidrug resistance-associated protein 3