Effects of bumetanide on bile flow in the pig

This study was performed on 12 anaesthetized pigs in order to examine the effect of the 'loop' diuretic bumetanide (inhibitor of Na,K,Cl-co-transport) on ductular bile secretion. It has previously been shown that administration of furosemide (a less potent 'loop' diuretic) to dogs and rats increases bile flow due to inhibition of ductular reabsorption of electrolytes and water. In group I (n = 6) bumetanide (median biliary concentration: 8.4 x 10(-3) mol l-1) increased bile flow and biliary concentration of HCO3 by 200% (116-320) and 50% (26-96), respectively. Biliary concentration of Cl was significantly decreased by 6% (2-12) following administration of bumetanide. In group II (n = 6) bile secretion was measured during secretin infusion (3 CU kg b. wt h-1) in the arterial pH range of 7.40-7.00, both before and after bumetanide administration in each animal. Bumetanide (median biliary concentration: 2.7 x 10(-3) mol I-1) did not significantly alter biliary secretion of water, HCO3, Na, K or Cl. Bile acid secretion was reduced by 30% from 43 (28-55) to 30 (17-41) mumol min-1 (P less than 0.05) while hepatic venous concentration of bile acids was raised by 90% (54-126) from 184 (113-309) to 350 (229-502) mumol l-1 (P less than 0.05) at slightly increased hepatic blood flow. Hepatic venous serum concentration of bumetanide was 4.8 (2.1-7.4) x 10(-4) mol l-1 (unbound fraction).(ABSTRACT TRUNCATED AT 250 WORDS)