Bile duct epithelium - frontiers in transport physiology. Boyer, James L. Department of Internal Medicine and Yale Liver Center, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510
APStracts 2:0196G, 1995.
Long thought to be merely a "sewer pipe" for the delivery of bile from hepatocytes to the gallbladder and intestine, the bile duct is now regarded as a highly dynamic structure whose epithelium consists of a heterogeneous cell population, capable of sustaining a wide variety of transport functions that contribute to the final composition of this complex secretion. Although comprising only 3-5% of the total population of liver cells, the intrahepatic bile duct epithelial (BDE) cells may produce as much as 40% of the daily output of bile, depending on the species, while at the same time modifying the organic and inorganic constituents of bile through many different re-absorptive mechanisms (36,46). Recent studies, carried out primarily in animal models from the rat, have clarified some of these transport mechanisms at the cellular and molecular level and are the subject of this review. However there has also been considerable interest in the involvement of this epithelium in both normal and malignant cell growth and regulation, and as targets for toxic and immunologic injury, particularly as related to the development of "vanishing bile duct diseases" in man. For these subjects, the interested reader is referred to several recent reviews (15,17,42).

Received 1 August 1995; accepted in final form 29 September 1995.
APS Manuscript Number G434-5.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 6 November 95