The effect of furosemide on the flow and composition of bile in the dog.

The effect of furosemide, a potent inhibitor of active sodium transport, on the amount and composition of bile was studied in the dog. Ten milligrams per kilogram of body weight of furosemide were injected intravenously to anesthetized dogs with a previously constructed fistula of the common bile duct. In all dogs, a 2.5 times increase in bile flow was observed concomitant with a 15 times increase in urinary output. The amount of bile flow decreased gradually and returned to control levels 60 to 75 minutes after furosemide injection. The choleretic effect was associated with a high increase in sodium, chloride and bicarbonate anions and with a smaller increase in potassium, phosphorus and calcium. The total amount of bilirubin alkaline phosphatase and cholesterol was not significantly affected, while the calculated output of inorganic salts increased. The results indicate that inhibition of sodium reabsorption by furosemide simultaneously affects the liver and kidney and that the increase in electrolyte solution is most likely caused by the inhibition of sodium reabsorption in the ductuli. Furosemide also may interfere with the sodium mediated secretory fraction at the canalicular level, but the predominant factor determining the increase in bile flow and electrolytes is inhibition of sodium reabsorption in the biliary ducts and ductuli.