Biliary lipid secretion during the prereplicative phase of rat liver regeneration

The prereplicative phase-related changes in spontaneous and taurocholate-induced biliary lipid secretion were studied in anaesthetized male Wistar rats (250 g). Rats underwent two-thirds hepatectomy 1, 6 or 12 h before starting to collect bile samples. As compared with non-hepatectomized rats, biliary lipid secretion was increased at 1 h after hepatectomy and then restored to values similar to the control group up to 12 h after hepatectomy. In separate experiments, taurocholate was infused (200 nmol/min/g calculated liver weight) through the jugular vein over 80 min. Both taurocholate-induced bile flow and bile acid output were similar in control and hepatectomized rats, regardless of the time of the prereplicative phase considered. By contrast, taurocholate-induced lecithin and cholesterol outputs were markedly modified. The former was lowered throughout the prereplicative phase, whereas the latter increased at 6 h and decreased at 12 h. In summary, these results indicate that shortly after hepatectomy bile acid-induced biliary lipid secretion is profoundly modified, probably due to changes in the plasma membrane involved in preparing the hepatocyte to enter the cell cycle.