ABSTRACT
Bile secretion serves different important functions. First, it is one of the main
mechanisms for the disposition of many endogenous and exogenous amphipatic compounds,
including drugs, toxins, and waste products. Second, it supplies bile salts to the
intestine, which is of crucial importance for the emulsification of dietary lipids.
In the last decade considerable progress has been achieved in the elucidation of the
process of bile formation. Several key transporters in the canalicular membrane have
been identified and characterized. This also holds for the mechanism of biliary lipid
secretion, where the lipid translocating function of a P-glycoprotein was found to
be indispensable for phospholipid secretion. Concomitantly, it became clear that bile
salt-induced lipid secretion is an extremely complex process, in which several steps
remain elusive. The production of mice with a specific defect in bilary lipid secretion
and the identification of an analogous inherited human disease have made it possible
to study the integrated function of biliary lipid secretion in whole body lipid homeostasis.
In this review we discuss our current understanding of hepatocanalicular lipid secretion
in this context. The pathologic consequences of defects in biliary lipid secretion
are discussed in another review in this issue.
KEYWORD
bile - phospholipid - cholesterol
