RT Journal Article
SR Electronic
T1 Induction of Hepatic Multidrug Resistance-Associated Protein 3 by Ethynylestradiol Is Independent of Cholestasis and Mediated by Estrogen Receptor
JF Drug Metabolism and Disposition
JO Drug Metab Dispos
FD American Society for Pharmacology and Experimental Therapeutics
SP 275
OP 280
DO 10.1124/dmd.112.047357
VO 41
IS 2
A1 María L. Ruiz
A1 Juan P. Rigalli
A1 Agostina Arias
A1 Silvina Villanueva
A1 Claudia Banchio
A1 Mary Vore
A1 Aldo D. Mottino
A1 Viviana A. Catania
YR 2013
UL http://dmd.aspetjournals.org/content/41/2/275.abstract
AB Multidrug resistance–associated protein 3 (Mrp3; Abcc3) expression and activity are up-regulated in rat liver after in vivo repeated administration of ethynylestradiol (EE), a cholestatic synthetic estrogen, whereas multidrug resistance-associated protein 2 (Mrp2) is down-regulated. This study was undertaken to determine whether Mrp3 induction results from a direct effect of EE, independent of accumulation of any endogenous common Mrp2/Mrp3 substrates resulting from cholestasis and the potential mediation of estrogen receptor (ER). In in vivo studies, male rats were given a single, noncholestatic dose of EE (5 mg/kg s.c.), and basal bile flow and the biliary excretion rate of bile salts and glutathione were measured 5 hours later. This treatment increased Mrp3 mRNA by 4-fold, detected by real-time polymerase chain reaction, despite the absence of cholestasis. Primary culture of rat hepatocytes incubated with EE (1–10 µM) for 5 hours exhibited a 3-fold increase in Mrp3 mRNA (10 µM), consistent with in vivo findings. The increase in Mrp3 mRNA by EE was prevented by actinomycin D, indicating transcriptional regulation. When hepatocytes were incubated with an ER antagonist [7α,17β-[9-[(4,4,5,5,5-Pentafluoropentyl)sulfinyl]nonyl]estra-1,3,5(10)-triene-3,17-diol (ICI182/780), 1 µM], in addition to EE, induction of Mrp3 mRNA was abolished, implicating ER as a key mediator. EE induced an increase in ER-α phosphorylation at 30 minutes and expression of c-Jun, a well-known ER target gene, at 60 minutes, as detected by Western blotting of nuclear extracts. These increases were prevented by ICI182/780. In summary, EE increased the expression of hepatic Mrp3 transcriptionally and independently of any cholestatic manifestation and required participation of an ER, most likely ER-α, through its phosphorylation.