Proteins in bile: how they get there and what they do.

Experimental hepatologists have recently directed increasing attention to biliary proteins. Studies have been performed to clarify which proteins are in bile, how they get there, and what they do. Results derived with a variety of analytical techniques and several experimental models indicate that there are many individual proteins in bile; some get there from plasma across hepatocytes via specific transport processes involving vesicles, while others are derived directly from cells in the liver. It appears that some proteins are released into bile after hepatocyte degradation while others may have important and specific functions. Quantitative or qualitative abnormalities of certain biliary proteins could be important in the pathophysiology of selected diseases.