Effect of organic anions and bile acid conjugates on biliary excretion of taurine-conjugated bile acid sulfates in the rat.
Biliary organic anion excretion is mediated by an ATP-dependent primary active transporter, canalicular multispecific organic anion transporter/multidrug resistance protein 2. On the other hand, a multiplicity of canalicular organic anion transporter/multidrug resistance protein 2 has been suggested. Therefore, to examine the effect of hydrophobicity on the substrate specificity of canalicular multispecific organic anion transporter/multidrug resistance protein 2, we examined the effect of organic anions and bile acid conjugates on biliary excretion of three taurine-conjugated bile acid sulfates with different hydrophobicity, taurolithocholate-3-sulfate, taurochenodeoxycholate3-sulfate, and taurocholate-3-sulfate in rats. Biliary excretions of these bile acid conjugates were delayed in Eisai hyperbilirubinemic rats. Biliary excretion of these bile acid conjugates was inhibited by sulfobromophthalein, whereas biliary excretion and taurocholate-3-sulfate was not inhibited by phenolphthalein glucuronide. Taurolithocholate-3-sulfate and ursodeoxycholate-3-glucuronide decreased biliary excretion of taurochenodeoxycholate-3-sulfate and taurocholate-3-sulfate, but ursodeoxycholate-3,7-disulfate did not affect biliary excretion of taurochenodeoxycholate-3-sulfate and taurocholate-3-sulfate. These findings indicate that very hydrophilic organic anions are not good substrates of canalicular multispecific organic anion transporter/multidrug resistance protein 2.
Uegaki
S
S
Department of Medicine, Teikyo University School of Medicine, Tokyo, Japan.
Takikawa
H
H
Yamanaka
M
M
D000818:Animals; D000838:Anions; D001646:Bile / Q000378:metabolism*; D001647:Bile Acids and Salts / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D008297:Male; D009930:Organic Chemicals / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013654:Taurine / Q000737:chemistry*
D000838:Anions; D001647:Bile Acids and Salts; D009930:Organic Chemicals; C020980:bile acid sulfates; D013654:Taurine