Bile formation and secretion.
Summary of "Bile formation and secretion."
Bile is a unique and vital aqueous secretion of the liver that is formed by the hepatocyte and modified down stream by absorptive and secretory properties of the bile duct epithelium. Approximately 5% of bile consists of organic and inorganic solutes of considerable complexity. The bile-secretory unit consists of a canalicular network which is formed by the apical membrane of adjacent hepatocytes and sealed by tight junctions. The bile canaliculi (∼1 μm in diameter) conduct the flow of bile countercurrent to the direction of portal blood flow and connect with the canal of Hering and bile ducts which progressively increase in diameter and complexity prior to the entry of bile into the gallbladder, common bile duct, and intestine. Canalicular bile secretion is determined by both bile salt-dependent and independent transport systems which are localized at the apical membrane of the hepatocyte and largely consist of a series of adenosine triphosphate-binding cassette transport proteins that function as export pumps for bile salts and other organic solutes. These transporters create osmotic gradients within the bile canalicular lumen that provide the driving force for movement of fluid into the lumen via aquaporins. Species vary with respect to the relative amounts of bile salt-dependent and independent canalicular flow and cholangiocyte secretion which is highly regulated by hormones, second messengers, and signal transduction pathways. Most determinants of bile secretion are now characterized at the molecular level in animal models and in man. Genetic mutations serve to illuminate many of their functions. © 2013 American Physiological Society. Compr Physiol 3:1035-1078, 2013.
Department of Medicine and Liver Center, Yale University School of Medicine, New Haven, Connecticut.
This article was published in the following journal.
Name: Comprehensive Physiology
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/23897680
- DOI: http://dx.doi.org/10.1002/cphy.c120027
Human BSEP mutations underlie progressive familial intrahepatic cholestasis type 2 (PFIC2). In the PFIC2 animal model, Bsep(-/-) mice, biliary secretion of bile salts (BS) is decreased, but that of ph...
The bile fluid contains various lipids that are secreted at the canalicular membrane of hepatocytes. As the secretion mechanism is still a matter of debate and a direct experimental observation of the...
Hepatocyte transplantation (HT) has been performed in patients with liver-based metabolic disease and acute liver failure as a potential alternative to liver transplantation in countries in which ethi...
Bile acid sequestrants have been used for decades for the treatment of hypercholesterolaemia. Sequestering of bile acids in the intestinal lumen interrupts enterohepatic recirculation of bile acids, w...
Studies have shown that the absence of bile in the gut lumen, either by bile duct ligation or bile diversion, induces mucosal injury. However, the mechanism remains elusive. In this study, the role of...
Endoscopic cholangiography is a procedure which is performed to image the bile duct and perform therapy like removal of bile duct stones. It is currently standard of care to remove stones ...
Our primary hypothesis is that bile acid sequestrant colesevelam and the antidiabetic drug metformin potentiates the secretion of the gut hormone glucagon-like peptide 1 (GLP-1).
The purpose of the study is to determine the best management of bile duct narrowing (stricture) due to inoperable tumors. The bile duct is a tube that carries bile formed in the liver to t...
To assess the bile acid composition of cystic bile and serum pharmaco¬kinetics after a 3-week treatment with UDCA and to correlate pharmacokinetic parameters of UDCA in bile and serum dur...
This project will compare the amount of bile acids and their kinetics in overweight and obese people with normal glucose metabolism, impaired glucose tolerance and frank type 2 diabetes. ...
Medical and Biotech [MESH] Definitions
The channels that collect and transport the bile secretion from the BILE CANALICULI, the smallest branch of the BILIARY TRACT in the LIVER, through the bile ductules, the bile ducts out the liver, and to the GALLBLADDER for storage.
FIBROSIS of the hepatic parenchyma due to obstruction of BILE flow (CHOLESTASIS) in the intrahepatic or extrahepatic bile ducts (BILE DUCTS, INTRAHEPATIC; BILE DUCTS, EXTRAHEPATIC). Primary biliary cirrhosis involves the destruction of small intra-hepatic bile ducts and bile secretion. Secondary biliary cirrhosis is produced by prolonged obstruction of large intrahepatic or extrahepatic bile ducts from a variety of causes.
A storage reservoir for BILE secretion. Gallbladder allows the delivery of bile acids at a high concentration and in a controlled manner, via the CYSTIC DUCT to the DUODENUM, for degradation of dietary lipid.
Minute intercellular channels that occur between liver cells and carry bile towards interlobar bile ducts. Also called bile capillaries.
Impairment of bile flow due to injury to the HEPATOCYTES; BILE CANALICULI; or the intrahepatic bile ducts (BILE DUCTS, INTRAHEPATIC).