Taurocholate transport by liver plasma membrane vesicles is not altered in cirrhotic rats

Recently, we have shown that taurocholate transport is impaired in hepatocytes isolated from CCl4 cirrhotic rats. Na+,K+-ATPase activity depends on the lipid composition of the surrounding membrane. Therefore, we performed this study in order to detect differences in plasma membrane composition and membrane functions between livers of CCl4 cirrhotic (n = 17) and of control rats (n = 15). After biochemical characterization of the animals we isolated basolateral and canalicular membrane vesicles and determined membrane enzyme activities, transport functions and lipid composition. We found no differences in the isolation characteristics of the plasma membranes between the two groups. The lipid composition of the membrane fractions was not altered, except for a lower cholesterol content in the canalicular membranes of the cirrhotic group (200 +/- 15 vs. 246 +/- 18 micrograms/mg protein, P less than 0.05). Taurocholate transport into basolateral membrane vesicles and marker enzyme activities of the membrane fractions were also equal in control and cirrhotic animals. We conclude that the plasma membrane composition and membrane enzyme/transport activities have returned to normal in CCl4 cirrhotic rats 14 days after cessation of exposure to CCl4. Thus, a disturbed transport system is not the cause for the observed decreased taurocholate transport into hepatocytes from cirrhotic rats. Even a cirrhotic liver has a high potential for recovery after acute CCl4 intoxication.