Water transport into bile and role in bile formation.
Formation of bile and generation of bile flow are driven by the active secretion of bile salts (BS), lipids and electrolytes into the canalicular and bile duct lumens followed by the osmotic movement of water. Although the transporting proteins involved in solute secretion have been cloned and their coordinated interplay defined both in health and disease, boosted by the discovery of the aquaporin water channels, only recently has considerable attention been addressed to the mechanism by which water, the major component of bile (> 95%), moves across the hepatobiliary epithelia. This review summarizes the novel acquisitions in liver membrane water transport and functional participation of aquaporin water channels in multiple aspects of hepatobiliary fluid balance. Emerging evidences suggesting involvement of aquaporins in the metabolic homeostasis of the hepatobiliary tract are also discussed.
Calamita
Giuseppe
G
Dept. of General and Environmental Physiology, University of Bari, Italy. calamita@biologia.uniba.it
Ferri
Domenico
D
Gena
Patrizia
P
Liquori
Giuseppa E
GE
Marinelli
Raúl A
RA
Meyer
Giuliano
G
Portincasa
Piero
P
Svelto
Maria
M
D000818:Animals; D020346:Aquaporins / Q000378:metabolism; D001646:Bile / Q000378:metabolism*; D001647:Bile Acids and Salts / Q000378:metabolism; D001648:Bile Canaliculi / Q000378:metabolism; D001652:Bile Ducts / Q000166:cytology / Q000378:metabolism; D006801:Humans; D014867:Water / Q000378:metabolism*
D020346:Aquaporins; D001647:Bile Acids and Salts; D014867:Water