title: Role of hepatic efflux transporters in regulating systemic and hepatocyte exposure to xenobiotics.
abstract: Hepatic efflux transporters include numerous well-known and emerging proteins localized to the canalicular or basolateral membrane of the hepatocyte that are responsible for the excretion of drugs into the bile or blood, respectively. Altered function of hepatic efflux transporters due to drug-drug interactions, genetic variation, and/or disease states may lead to changes in xenobiotic exposure in the hepatocyte and/or systemic circulation. This review focuses on transport proteins involved in the hepatocellular efflux of drugs and metabolites, discusses mechanisms of altered transporter function as well as the interplay between multiple transport pathways, and highlights the importance of considering intracellular unbound concentrations of transporter substrates and/or inhibitors. Methods to evaluate hepatic efflux transport and predict the effects of impaired transporter function on systemic and hepatocyte exposure are discussed, and the sandwich-cultured hepatocyte model to evaluate comprehensively the role of hepatic efflux in the hepatobiliary disposition of xenobiotics is characterized.
authors.affiliation: Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599; email: npfeifer@email.unc.edu , kbrouwer@unc.edu.
authors.forename: Nathan D
authors.initials: ND
authors.lastname: Pfeifer
authors.forename: Rhiannon N
authors.initials: RN
authors.lastname: Hardwick
authors.forename: Kim L R
authors.initials: KL
authors.lastname: Brouwer
mesh_terms: D000818:Animals; D001646:Bile / Q000378:metabolism; D001692:Biological Transport; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D004195:Disease Models, Animal; D004347:Drug Interactions; D022781:Hepatocytes / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D015262:Xenobiotics / Q000494:pharmacology*
chemical_list: D002352:Carrier Proteins; D015262:Xenobiotics