title: Influence of omeprazole on multidrug resistance protein 3 expression in human liver.
abstract: Multidrug resistance protein (MRP) 3 transports bile salts and conjugated xenobiotics from cells (hepatocytes and enterocytes) into the blood. Hepatic MRP3 expression is low under normal conditions but is markedly up-regulated during cholestasis. Since little is known about additional factors increasing human hepatic MRP3 expression, we investigated the variability of MRP3 expression in a large collection of human livers and factors contributing to variable MRP3 expression in liver and HepG2 cells. MRP3 was measured in 62 human livers from patients with and without omeprazole treatment and in HepG2 cells with and without omeprazole or beta-naphthoflavone treatment. Livers of patients treated with omeprazole showed 4.8-fold (P < 0.0001) higher MRP3 protein expression compared with the remainder of the population. Accordingly, MRP3 mRNA and protein were induced 2.4- and 1.8-fold, respectively (P < 0.01 and P < 0.05), in HepG2 cells treated with omeprazole. Finally, MRP3 was induced in HepG2 cells by beta-naphthoflavone. In summary, treatment with omeprazole and beta-naphthoflavone is a determinant of variable human hepatic MRP3 expression.
authors.affiliation: Dr. Margarete Fischer-Bosch-Institute of Clinical Pharmacology, Stuttgart, Germany.
authors.forename: Monika
authors.initials: M
authors.lastname: Hitzl
authors.forename: Kathrin
authors.initials: K
authors.lastname: Klein
authors.forename: Ulrich M
authors.initials: UM
authors.lastname: Zanger
authors.forename: Peter
authors.initials: P
authors.lastname: Fritz
authors.forename: Andreas K
authors.initials: AK
authors.lastname: Nüssler
authors.forename: Peter
authors.initials: P
authors.lastname: Neuhaus
authors.forename: Martin F
authors.initials: MF
authors.lastname: Fromm
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B / Q000096:biosynthesis*; D018528:ATP-Binding Cassette Transporters / Q000096:biosynthesis*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D005260:Female; D015870:Gene Expression / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009853:Omeprazole / Q000494:pharmacology*; D012333:RNA, Messenger / Q000096:biosynthesis
chemical_list: D018435:ATP Binding Cassette Transporter, Subfamily B; D018528:ATP-Binding Cassette Transporters; D012333:RNA, Messenger; C095122:multidrug resistance protein 3; D009853:Omeprazole