glucagon

(noun)

a hormone, produced by the pancreas, that opposes the action of insulin by stimulating the production of sugar

Related Terms

Examples of glucagon in the following topics:

  • Hormonal Regulation of Metabolism

    • The levels of glucose in the blood are regulated by the hormones insulin and glucagon from the pancreas, and T3 and T4 from the thyroid.
    • Insulin and glucagon are the two hormones primarily responsible for maintaining homeostasis of blood glucose levels.
    • Glucagon also stimulates absorption of amino acids from the blood by the liver, which then converts them to glucose.
    • Rising blood glucose levels inhibit further glucagon release by the pancreas via a negative feedback mechanism.
    • In this way, insulin and glucagon work together to maintain homeostatic glucose levels .

  • Pancreas

    • As an endocrine gland, the pancreas produces several important hormones,such as insulin and glucagon, which are secreted into the bloodstream to regulate blood sugar levels, along with other activities throughout the body.
    • The pancreatic islets contain two primary cell types: alpha cells, which produce the hormone glucagon, and beta cells, which produce the hormone insulin.
    • As blood glucose levels decline, alpha cells release glucagon to raise the blood glucose levels by increasing rates of glycogen breakdown and glucose release by the liver.
    • The alpha and beta cells produce glucagon and insulin, respectively.

  • Epinephrine and Norepinephrine

    • Binding to α-adrenergic receptors inhibits insulin secretion by the pancreas, stimulates glycogenolysis (the breakdown of glycogen) in the liver and muscle, and stimulates glycolysis (the metabolic pathway that converts glucose into pyruvate) in muscle. β-Adrenergic receptor binding triggers glucagon secretion in the pancreas, increased adrenocorticotropic hormone (ACTH) secretion by the pituitary gland, and increased lipolysis by adipose tissue.

  • Adrenal Glands

    • These hormones, together with such hormones as insulin and glucagon, are important regulators of the ionic environment of the internal fluid.

  • Control of Homeostasis

    • However, if an animal has not eaten and blood glucose levels decrease, this is sensed in a different group of cells in the pancreas: the hormone glucagon is released, causing glucose levels to increase.