Chapter category: Channels and Transporters
The ABC of Canalicular Transport
Molecular Pathogenesis of Cholestasis
Edited by: Michael Trauner and Peter JansenISBN: 0-306-48240-1
» Get more information about this book at landesbioscience.com «
Chapter authors:
Bile formation is a regulated process and depends on the coordinated action of a number of transporter proteins in the sinusoidal (basal) and canalicular (apical) domains of the hepatocyte. The secretion of substances in the canalicular lumen is mediated by a set of ATP-dependent transport proteins. Dysfunction of any of these proteins leads to retention of substrates, with e.g., conjugated hyperbilirubinemia or cholestasis as a result. In recent years many of the transport proteins involved in bile formation have been identified, cloned, and functionally characterized. In this chapter we will shortly describe the present knowledge regarding function and regulation of the primary active transport proteins involved in canalicular secretion of biliary components.
Additional chapters from this book:
Disorders of Bile Acid Transport
Bile salts take part in a rather efficient enterohepatic circulation in which most of the secreted bile salts are reclaimed by absorption in the terminal ileum. In the liver the sodium dependent tau...
Pathology of Cholestasis
C formation may give rise to extensive parenchymal changes, without significant alterations in biliary tree morphology. Sepsis or systemic inflammatory conditions also can cause severe hepatocellula...
Bile Acid-Mediated Apoptosis in Cholestasis
H injury by inducing apoptosis. Toxic bile acids induce apoptosis by activating cell surface membrane death receptors. The activated death receptors stimulate a signaling cascade involving the pro-a...
Hepatocyte Transplantation and Liver-Directed Gene Therapy
The research on liver-directed gene therapy and hepatocyte transplantation has progressed in parallel. Hepatocytes, with or without genetic modification have been used to introduce normal genes ...
Genetics, Mutations and Polymorphisms
Genetic approaches complement functional approaches to the study of hereditary disease, and have contributed substantially to our understanding of the biology of enterohepatic circulation in hea...
Fat Absorption and Lipid Metabolism in Cholestasis
The liver has a central role in control of various aspects of lipid metabolism. Primarily, the liver produces bile, constituents of which are required for efficient intestinal fat absorption. Ad...
Hepatocellular Transport Systems: Basolateral Membrane
The basolateral membrane of hepatocytes is equipped with efficient transport systems for uptake of bile salts (Ntcp/NTCP) and xenobiotics (Oatps/OATPs). Under physiological conditions these tran...
Genetic Defects in Biliary Lipid Transport
In terms of solute mass, lipids are the second most important component of bile. Biliary lipids mainly consist of phospholipid (almost exclusively phosphatidylcholine; PC) and cholesterol. The...
Gap Junctions in the Liver
Gap junctions are hexameric hemichannels that are inserted into the plasma membrane and allow for direct exchange of cytosolic contents among adjacent cells. Connexin 26 and connexin 32 are the sp...
Medical Therapy of Cholestatic Liver Diseases
Cholestasis and its sequelae are the hallmark of chronic cholestatic liver diseases and can be a feature of virtually all liver diseases at some point. Ursodeoxycholic acid (UDCA), a dihydroxy bil...
Pathophysiological Basis of Pruritus and Fatigue in Cholestasis
Fatigue and pruritus are subjective complaints which are extremely common amongst patients with cholestasis, significantly impairing the quality of life of these patients. The genesis of these...
Bone Disease in Chronic Cholestatic Liver Disease
Harold Dobnig and Astrid Fehrleiter
Patients with chronic cholestatic liver disease are especially prone to osteoporosis. Hepatic osteodystrophy typically presents as low turnover osteoporosis with initially normal bone resorption that...
Acquired Alterations in Transporter Expression and Function in Cholestasis
Exposure to cholestatic injury (e.g., drugs, hormones, proinflammatory cytokines, biliary obstruction/destruction), hereditary mutations of transporter genes, or the combination of both result i...
Drug-induced cholestatic liver disease
Drug induced cholestatic liver disease is a subtype of liver injury that is characterized by predominant elevations of alkaline phosphatase and bilirubin secondary to the administration of a hep...
Primary sclerosing cholangitis
Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disorder of the intrahepatic and/or extrahepatic bile ducts. PSC is characterized by concentric obliterative fibrosis and bile...
Molecular Basis of Primary Biliary Cirrhosis
Primary biliary cirrhosis (PBC) can be defined by the triad of positive PBC-specific autoantibodies (antimitochondrial antibodies (AMA) in >95%), cholestatic liver function tests and diagnostic ...
Hepatic Copper Transport
Copper is an essential nutrient that is required in a number of critical metabolic path ways. This metal is absorbed in the stomach and duodenum, stored in the liver and excreted in the bile. The...
Transport of Bilirubin and its Conjugates across Hepatocellular Membrane Domains and the Conjugated Hyperbilirubinemia of Dubin-Johnson Syndrome
Bilirubin, the end product of heme catabolism, needs to be taken up into hepatocytes and is then glucuronidated within the cells prior to its excretion via bile. Members of the SLC21A family in ...
Hepatic Drug Metabolism
The liver plays an important role in the metabolism of xenobiotics and the metabolic reactions are mediated by many different kinds of enzymes. These enzymes mediate the detoxification in most c...
Transcriptional Regulation of Hepatobiliary Transporters
The expression and activities of hepatobiliary transporter genes is a critical component of liver function. Both sinusoidal and canalicular membrane transporters are responsible for the coordina...
The Pathobiology of cholangiocytes
In this chapter, we first review the bile duct structure, then the intracellular mechanisms involved in ductal secretion and absorption. The modulation of ductal secretion by hormo...
Cholestasis: An Intracellular "Traffic Jam"
Mutations in the coding region of BSEP which result in its absence from the bile canalicular membrane are manifested by progressive cholestasis and liver damage. We have proposed that defects ...
The ABC of Canalicular Transport
Bile formation is a regulated process and depends on the coordinated action of a number of transporter proteins in the sinusoidal (basal) and canalicular (apical) domains of the hepatocyte. The ...
Mechanisms of Bile Formation—An Introduction
The formation of bile is a unique and vital function of the liver. Failure to form bile results in progressive cholestatic liver injury and death. Knowledge of the mechanism of bile formation ha...
Signal Transduction in Bile Formation and Cholestasis
Bile formation involves vectorial transport of solutes from blood to bile and is dependent on coordinated activities of various solute transporters located at the basolateral and apical membra...

