Mechanism and regulation of hepatic bile production. With special reference to the bile acid-independent canalicular bile formation.
The main purpose of the present study was to examine the mechanism and regulation of hepatic bile acid-independent canalicular bile production. The experiments were performed on fasted, anesthetized intact cats and rats with acute bile fistulae, on perfused rat livers and with isolated liver plasma membranes from these species. The effect of insulin and glucagon on bile production was examined. The possible role of Na, K-ATPase for bile production was studied by administration of inhibitors (ouabain, vanadate) of this enzyme. Also the effect of insulin and glucagon on hepatic Na, K-ATPase was examined. Finally, the literature describing this field is reviewed and discussed in relation to the findings of the present experiments. It is concluded, that a part of the canalicular bile is produced independently of bile acid secretion and that the formation of this fraction can be stimulated by insulin and glucagon via a direct action of the hormones on the liver. It seems that interaction between the two canalicular fractions of bile formation is possible. The mechanism of bile acid-independent canalicular bile formation is still unsettled and conclusive evidence for the direct involvement of hepatic Na, K-ATPase in the secretion of this fraction is lacking.
D000818:Animals; D001646:Bile / Q000378:metabolism*; D001647:Bile Acids and Salts / Q000096:biosynthesis*; D002415:Cats; D002462:Cell Membrane / Q000201:enzymology; D005934:Glucagon / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology; D008099:Liver / Q000201:enzymology / Q000378:metabolism*; D008102:Liver Circulation; D008297:Male; D010042:Ouabain / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors / Q000378:metabolism; D014638:Vanadates; D014639:Vanadium / Q000494:pharmacology
D001647:Bile Acids and Salts; D007328:Insulin; D014639:Vanadium; D014638:Vanadates; D010042:Ouabain; D005934:Glucagon; D000254:Sodium-Potassium-Exchanging ATPase