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Altered pharmacokinetics and hepatic uptake of TBuMA in ethynylestradio-induced cholestasis
- Hong, Soon-Sun, Choi, Jong-Moon, Jin, Hyo-Eon, Shim, Chang-Koo
- Archives of pharmacal research 2006 v.29 no.4 pp. 323-327
- bile salts, cations, hepatocytes, intrahepatic cholestasis, intravenous injection, liver, pharmacokinetics, rats, tritium
- The objective of this study was to examine the pharmacokinetics of organic cations in intrahepatic cholestatic rats. A pretreatment with 17α-ethynylestradiol was used to induce intrahepatic cholestasis, and tributylmethylammonium (TBuMA) was used as a representative model organic cation. When [³H]TBuMA was intravenously administered, the AUC value for TBuMA was significantly increased by 79% in cholestasis, and its total systemic clearance was consequently decreased by 46%. In addition, thein vivo hepatic uptake clearance of TBuMA from the plasma to the liver was decreased by 50% in cholestasis. The concentration of bile salts in plasma was increased by 2.1 fold in cholestatic rats. Since TBuMA forms ion-pair complexes with anionic components such as bile salts, the decreased hepatic uptake of TBuMA in cholestasis may be due to a change in endogenous components, e.g., bile salts in the plasma. In isolated normal hepatocytes, the uptake clearance for TBuMA in the presence of cholestatic plasma was decreased by 20% compared with normal plasma. Therefore, we conclude that the inhibition of the hepatic uptake process by the cholestasis may be in part due to the increased formation of ion-pair complexes of TBuMA with bile salts in the plasma.