ROLE OF DUCTULAR BILE WATER REABSORPTION IN CANINE BILE SECRETION

  • 1 January 1985
    • journal article
    • research article
    • Vol. 106  (2) , 154-161
Abstract
To quantitate ductular and/or ductal bile H2O reabsorption and to define its role in hepatic bile formation, spontaneous and taurocholate-stimulated bile flow and composition were measured in anesthetized dogs postprandially (n = 4) and after 24 h (n = 4) and a 48 h (n = 4) fasting period. Spontaneous bile flow in fed dogs (0.344 .+-. 0.116 .mu.l/min/g liver tissue) was significantly higher than that in 24 h (0.179 .+-. 0.046 .mu.l/min/g) and 48 h fasted animals (0.096 .+-. 0.085 .mu.l/min/g). One 48 h fasted dog was virtually cholestatic (spontaneous bile flow 0.004 .mu.l/min/g): another 48 h fasted animal had a mean bile flow rate as low as 0.036 .mu.l/min/g. Calculated ductublar bile H20 reabsorption (C 14-erythritol bilary clearance minus bile flow) was the same in the 3 groups of animals (0.166 .+-. 0.056, 0.208 .+-. 0.033 and 0.204 .+-. 0.055 .mu./min/g, respectively). Administration of sodium taurocholate (0.5 to 2.0 .mu.mol/min/kg) revealed intact canalicular secretory capacity in all dogs. No change in bile H2O reabsorption rate was observed during choleresis. Bile chloride and bicarbonate concentrations during spontaneous secretion were significantly lower in 48 h fasted dogs when compared with fed animals. In the 2 48 h fasted dogs with a very low rate of spontaneous bile flow, chloride and bicarbonate concentrations in hepatic bile were as low as those seen in gallbladder bile (5 - 10 mEq/L) and increased during taurocholate choleresis. In the anesthetized dog, bile H20 is reabsorbed at the distal bile ductules and/or ducts at an approximate rate of 0.2 .mu.l/min/g, possibly through a Na-coupled chloride transport mechanism as in the gallbladder. Cholestasis may develop under those conditions in which bile secretion is reduced to a rate similar to that of H20 reabsorption.