Cardiovascular Effects of Glucagon

Glucagon, 50 μg/kg, was given as a bolus injection into the pulmonary artery to ten patients with severe heart disease. In all patients an increase in cardiac output was found, those with highest initial output increasing most. Oxygen consumption was unaltered, systemic vascular resistance decreased, potassium levels fell, whereas glucose and insulin levels rose. No effect was observed on heart rate. In four other patients the same registrations were made after infusion of 90 ml 30% glucose with 8 IU insulin. No effect on cardiac output was observed, although glucose levels increased and potassium levels fell to the same extent as after glucagon injection. In the same patients the cardiac output increased after glucagon injection. The investigation supports previous reports that glucagon might be a useful therapeutic agent in low output failure.