Insulin resistance and delayed clearance of peptide hormones in cirrhotic rat liver

Abstract

Clearance of porcine insulin, glucagon, and human growth hormone was measured in intact perfused cirrhotic and normal rat livers. Binding and degradation of 125I-insulin by hepatocytes isolated from cirrhotic and normal livers were also studied. The half-lives (t1/2) of immunoreactive insulin and glucagon were 14.0 +/- 3.1 and 9.6 +/- 2.1 min in normal livers and 26.0 +/- 6.1 and 25.0 +/- 7.1 min in cirrhotic livers (P less than 0.001). Insulin binding and degradation by hepatocytes from control and cirrhotic livers showed no significant differences. Intraportal insulin infusion in perfusion studies suppressed glucagon-stimulated increases in glucose output from control livers but failed to suppress glucose production by cirrhotic livers, suggesting the presence of hepatic insulin resistance in cirrhosis. Impaired clearance of insulin and glucagon by the intact cirrhotic liver and normal binding and degradation of insulin by isolated hepatocytes suggest that factors such as intrahepatic fibrosis and shunting and postbinding defects may be responsible for the impaired hormone clearance and hepatic insulin resistance.