Somatostatin infusion in liver cirrhosis: glucagon control of glucose homeostasis.

Abstract

In order to evaluate the role of glucagon in blood glucose homeostasis in liver cirrhosis, ten normal subjects and ten cirrhotic patients were infused with somatostatin (500 μg/h for 5 h) with and without glucagon (3 mg/kg/h) administration. Somatostatin infusion brought about a fall in plasma glucose both in normal (37%) and cirrhotic (41%) subjects in the first 90 minutes. In normal subjects, this was followed by a rise in plasma glucose (147±2 mg/dl at 5 h), while in cirrhotics no rise in plasma glucose was observed (50±1 mg/dl at 5 h). Plasma insulin and glucagon levels were suppressed in both normal and cirrhotic subjects. Addition of glucagon to the somatostatin infusion caused a two fold rise in plasma glucose level to 183±12 mg/dl at 4 h in normal subjects; a much smaller increase was found in the cirrhotic group (105±3 mg/dl at 4 h). When the infusion was stopped, plasma glucose fell both in normal and cirrhotic subjects (102±14 and 87±2 mg/dl at 6 h respectively). Subsequently, hyperglucagonaemia recurred in the cirrhotic patients (319 ±31 pg/ml). A rebound of plasma insulin was observed in normal subjects (47±8 μU/ml) which did not occur in the cirrhotics (16±2 μU/ml). Thus when both insulin and glucagon were suppressed by somatostatin infusion, euglycaemia occurred in cirrhotic subjects only when glucagon concentration was restored exogenously. We conclude that glucagon is important in glucose homeostasis in patients with liver cirrhosis.