Morphology of liver cell tight junctions in ethinyl estradiol induced cholestasis

Using freeze-fracture techniques the junctional complex of the hepatocytes in female rats is studied after ethinyl estradiol induced cholestasis. The gap junctions are not changed in this situation in contrast to the altered pattern found in extrahepatic bile duct obstruction. The more or less parallel tight junctional strands around the canalicular lumen are converted into a irregular loose network after estradiol treatment in a similar way as in extrahepatic cholestasis. These modifications in the geometrical arrangement of the strands suggest an increase permeability through the tight junctions so that a backward diffusion of biliary components through intercellular escape is possible.