Effects of Glucagon on Myocardial Oxygen Consumption and Coronary Blood Flow in Man and in Dog
The effects of intravenous administration of glucagon (50 µg/kg) on left coronary blood flow and myocardial oxygen consumption were studied in nine patients during diagnostic cardiac catheterization and in six open-chested anesthetized dogs. Coronary blood flow was measured with the 133Xe washout technic in man, and with an electromagnetic flowmeter placed around the left anterior descending coronary artery in the dogs. In the patients, glucagon produced a 31% increase in coronary blood flow and a 29% increase in myocardial oxygen consumption, with no change in coronary arteriovenous (A-V) O2 difference across the heart. In the dogs glucagon produced a 114% increase in coronary blood flow and a 131% increase in myocardial oxygen consumption, again with no change in coronary A-V O2 difference. Thus glucagon is a secondary coronary vasodilator in both man and dog. The modest chronotropic and inotropic effects of glucagon observed in man were only half as great as those observed in the dog. Part or all of this difference in dose-response relationship between the two species may be related to the different experimental conditions of the study.
- Coronary A-V O2 difference
- Coronary vascular resistance
- Pressure-time per minute
- Secondary coronary vasodilator
- Left ventricular work
- 133Xe washout
- Received October 27, 1969.
- Accepted December 2, 1969.
- © 1970 American Heart Association, Inc.