Glucagon

Article By:

Bromer, William W. Eli Lilly and Company, Indianapolis, Indiana.

Washington, M. Todd Department of Biochemistry, University of Iowa, Iowa City, Iowa.

Last reviewed:January 2020

DOI:https://doi.org/10.1036/1097-8542.291900

The protein hormone secreted by the alpha cells of the pancreas that is known to influence a wide variety of metabolic reactions. Glucagon, along with insulin and other hormones, plays a role in the complex and dynamic process of maintaining adequate supplies of blood sugar (glucose). Glucagon has often been called the hyperglycemic-glycogenolytic factor because it causes the breakdown of liver glycogen to sugar (a process known as glycogenolysis) and thereby increases the concentration of sugar in the bloodstream (a condition known as hyperglycemia). Glucagon may also be involved in the regulation of protein and fat metabolism, gastric acid secretion and gut motility, excretion of electrolytes (such as sodium, potassium, and chloride) by the kidney, contractility of heart muscle, and release of insulin from the pancreas. On the basis of present evidence, glucagon may be considered to act in a close and subtle cooperation with other hormones and with enzymes to help control the dynamic processes of life. Glucagon is used in human medicine, chiefly in certain diabetic conditions when a dangerously low blood sugar must be rapidly raised. See also: Carbohydrate metabolism; Diabetes; Endocrine mechanisms; Enzyme; Glycogen; Hormone; Insulin; Liver; Pancreas

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