US EPA

8222423 

Journal Article 

Effect of acetaminophen on expression and activity of rat liver multidrug resistance-associated protein 2 and P-glycoprotein 

Ghanem, CI; Gómez, PC; Arana, MC; Perassolo, M; Ruiz, ML; Villanueva, SSM; Ochoa, EJ; Catania, VA; Bengochea, LA; Mottino, AD 

2004 

Yes 

Biochemical Pharmacology
ISSN: 0006-2952
EISSN: 1873-2968 

68 

4 

791-798 

English 

15276087 

10.1016/j.bcp.2004.05.014 

We evaluated the effect of acetaminophen (APAP), given as a single, 1 g/kg body weight dose, on expression and activity of rat liver multidrug resistance-associated protein 2 (Mrp2) and P-glycoprotein (P-gp), two major canalicular drug transporters. The studies were performed 24 h after administration of the drug. APAP induced an increase in plasma membrane content of Mrp2 detected by western blotting, consistent with increased detection of the protein at the canalicular level by immunoflourescence microscopy. In vivo biliary excretion of dinitrophenyl-S-glutathione, a well known Mrp2 substrate, was slightly but significantly increased by APAP, agreeing well with upregulation of the transporter. Basal biliary excretion of oxidized glutathione, an endogenous Mrp2 substrate, was also increased by APAP, likely indicating increased hepatic synthesis as a result of APAP-induced oxidative stress followed by accelerated canalicular secretion mediated by Mrp2. APAP also increased the expression of P-gp detected by western blotting and immunofluorescence microscopy as well as the in vivo biliary secretory rate of digoxin, a model P-gp substrate. Because specific APAP-conjugated metabolites are Mrp2 substrates, we postulate that induction of Mrp2 by APAP may represent an adaptive mechanism to accelerate liver disposition of the drug. In addition, increased Mrp2-mediated elimination of oxidized glutathione may be essential in maintaining the redox equilibrium in the hepatocyte under conditions of APAP-induced oxidative stress. © 2004 Elsevier Inc. All rights reserved. 

1-chloro-2,4-dinitrobenzene; acetaminophen; alanine aminotransferase; alkaline phosphatase; aspartate aminotransferase; ATP-binding cassette; dinitrophenyl-S-glutathione; oxidized glutathione; reduced glutathione