RT Journal Article SR Electronic T1 Involvement of an Organic Anion Transporter (Canalicular Multispecific Organic Anion Transporter/Multidrug Resistance-Associated Protein 2) in Gastrointestinal Secretion of Glutathione Conjugates in Rats JF Journal of Pharmacology and Experimental Therapeutics JO J Pharmacol Exp Ther FD American Society for Pharmacology and Experimental Therapeutics SP 433 OP 439 VO 292 IS 1 A1 Yasumasa Gotoh A1 Hiroshi Suzuki A1 Setsuo Kinoshita A1 Tomoko Hirohashi A1 Yukio Kato A1 Yuichi Sugiyama YR 2000 UL http://jpet.aspetjournals.org/content/292/1/433.abstract AB We investigated the role of cMOAT/MRP2 (canalicular multispecific organic anion transporter/multidrug resistance-associated protein 2) in the intestinal secretion of organic anions by comparing the behavior in Sprague-Dawley (SD) rats and Eisai hyperbilirubinemic rat (EHBR) whose cMOAT/MRP2 is hereditarily defective. After i.v. administration of 1-chloro-2,4-dinitrobenzene (30 μmol/kg), the biliary and intestinal excretion of its glutathione conjugate 2,4-dinitrophenyl-S-glutathione (DNP-SG), a substrate for cMOAT/MRP2, was significantly reduced in EHBR compared with SD rats. This result also was confirmed by Ussing chamber studies; DNP-SG showed 1.5-fold greater serosal-to-mucosal flux compared with the mucosal-to-serosal flux in SD rats, whereas a similar flux was observed in both directions in EHBR. In addition, metabolic inhibitors reduced the preferential serosal-to-mucosal flux of DNP-SG in SD rats. In everted sac studies, intestinal secretion clearance, defined as the efflux rate of DNP-SG into the mucosal side divided by the area under the curve on the serosal side, was significantly lower in the jejunum of EHBR than that in SD rats. Northern blot analyses demonstrated the highest mRNA level of cMOAT/MRP2 in the jejunum, which is in good agreement with the results of the everted sac studies. These results suggest that cMOAT/MRP2 is involved in the secretion of organic anions in the small intestine. The American Society for Pharmacology and Experimental Therapeutics