Effects of Long-term Infusion of Glucagon on Carbohydrate Metabolism, Insulin and Growth Hormone Secretion in Patients with Congestive Heart Failure

Abstract

Glucagon was given by continuous intravenous infusion for ninety-six hours to eight patients with severe congestive heart failure. The dose was 4 or 2 mg. per hour. Results were similar in both groups and are presented together. Mean fasting blood sugar increased significantly during infusion (from 87 to 103 mg./100 ml.). Mean fasting serum immunoreactive insulin (IRI) increased considerably (from 9.1 to 32.0 μU/ml.) and mean fasting serum immunoreactive growth hormone (HGH) increased from 2.8 to 11.9 ng./ml. Intravenous glucose tolerance tests were performed before and during glucagon infusion. The glucose disappearance rate (K-value) declined significantly during the infusions (from a mean of 0.85 to 0.46), although serum IRI responses to the intravenous glucose were much higher than before. Serum HGH levels were not suppressed by the glucose and sometimes even showed a rise. A carbohydrate-rich meal induced the same rises in blood sugar during glucagon infusion as before, but serum IRI responses were much higher during glucagon, and elevated serum HGH values were not normalized. It is concluded that long-term infusion of pharmacological doses of glucagon to patients with cardiac insufficiency leads to a state of mild carbohydrate intolerance, characterized by some increase in fasting blood sugar and decrease in glucose disappearance rate, in spite of very considerable rises in serum IRI. This diabetes-like state may be accounted for by elevated levels of serum HGH, although other insulin-antagonistic factors may be involved.