Bile salt and glutathione coefflux mediated by multidrug resistance protein MRP4 (ABCC4), a basolateral transporter of the hepatocyte

摘要

Under normal physiological conditions, bile salts are rapidly transported across the canalicular membrane of human hepatocytes by the ATP-binding cassette transporter BSEP (bile salt export pump; ABCB11). However, when bile salt transport into bile is affected because of an impaired function of BSEP and/or biliary obstruction, efflux of bile salts across the basolateral hepatocyte membrane can decrease the accumulation of bile salts within the hepatocytes. This overflow mechanism may be mediated by basolateral efflux pumps. Although MRP3 (ABCC3) is localized to the basolateral membrane of human hepatocytes, it has been reported to be a poor transporter of cholyltaurine (C-tau) and cholylglycine (C-gly). Human MRP3, therefore, only accounts for part of the bile salt efflux across the basolateral membrane.