Effect on Bile Formation of Inhibitors of Sodium Transport

Abstract

THERE are two well documented mechanisms of bile formation: active secretion of bile acids by hepatocytes and subsequent osmotic diffusion of water and electrolytes^1,2, and secretion of an electrolyte solution by the biliary epithelium, chiefly in response to administration of secretin^2,3. Several observations, however, suggest the possibility of an additional mechanism, especially in rodents, which have a very high bile flow. For example, bile flow remains high after bile salt depletion following bile duct cannulation in the rat⁴; and bile flow is high in the isolated perfused rat liver, with no entero-hepatic circulation of bile salts⁵. To explain these observations, inorganic ion secretion by the hepatocyte has been postulated^6,9. Previous studies here gave results consistent-with a large hepatocytic bile salt independent fraction in the rabbit amounting to 60 µl./min/kg body weight, that is 60 per cent of the spontaneous bile flow in this animal^7,8. To test the hypothesis that this fraction may result from active inorganic ion transport, we studied the effects on bile formation of known inhibitors of active sodium transport.