Plasma insulin, C-peptide, and blood glucose in portal, hepatic and peripheral veins in liver cirrhosis. Effect of intravenous tolbutamide

Abstract

The responses of portal, hepatic and peripheral venous blood glucose (BG), plasma insulin (IRI) and C-peptide (IRC) levels to iv tolbutamide (200 mg) have been determined in 9 non-diabetic patients with liver cirrhosis and in 6 control subjects. The basal levels of plasma IRI and IRC were similar in patients and controls as were the portal and peripheral BG levels. In the hepatic vein, however, the BG-levels were higher in cirrhotic patients than in controls. After tolbutamide administration the BG-levels were unchanged in the cirrhotic patients but a significant fall in hepatic vein BG was observed in controls. In both groups of subjects the highest post-tolbutamide IRI-levels were found in the portal vein whereas the corresponding IRC-levels were as high in the hepatic as in the portal vein. The increments of portal venous IRI and IRC were significantly higher in controls as compared to the cirrhotic patients. Nevertheless, in the peripheral veins the increments of IRI and IRC were very similar in both groups of subjects or even less in the control subjects. The results suggest that in patient with liver cirrhosis the secretion of insulin is not increased but slightly decreased. The production of glucose by the liver also seems to be increased either due to insulin resistance or portal venous shunting of insulin.