Effect of acute insulin administration on biliary lipid secretion by the diabetic rat

The insulin-deficient state induces profound changes in bile formation. The present work was to test the effect of acute insulin administration on lipid secretion into bile in diabetic rats. Diabetes was induced by streptozotocin injection (6 mg/100 g body-weight, i.p., 6 days before the experiments). Bile formation was stimulated by taurocholate infusion (0.5 mumol/min/100 g body-weight). Intravenous administration of insulin (bolus: 100 mU/100 g body-weight, plus infusion: 5 mU/min/100 g body-weight) induced choleresis accompanied by a slight and transient enhancement in bile acid output which was similar to that found in lecithin and cholesterol output in the control group. However, insulin induced a rapid and significant (P less than 0.05) reduction in biliary lipid output in the diabetic rats. These results suggest that insulin may play an important role in mechanisms other than synthesis involved in the supply of biliary lipids towards the canaliculi.