According to current views, canalicular (hepatocytic) bile water transport is mostly an osmotic process: water and inorganic electrolytes flow into bile canaliculi along an osmotic gradient resulting from the extrusion of solutes by the hepatocytes into the canalicular lumen (1-3). Although, over the past decade, much data have been generated, the overall understanding of the cellular and molecular events responsible for transepithelial transport in the liver is still poor and many aspects are controversial. Because recent comprehensive reviews of the mechanisms of bile flow are available (3, 4),