glucagon


Also found in: Dictionary, Thesaurus, Medical, Acronyms, Wikipedia.
Related to glucagon: somatostatin, glucagon test

glucagon

(glo͞o`kəgŏn), hormonehormone,
secretory substance carried from one gland or organ of the body via the bloodstream to more or less specific tissues, where it exerts some influence upon the metabolism of the target tissue.
..... Click the link for more information.
 secreted by the α cells of the islets of Langerhans, specific groups of cells in the pancreaspancreas
, glandular organ that secretes digestive enzymes and hormones. In humans, the pancreas is a yellowish organ about 7 in. (17.8 cm) long and 1.5 in. (3.8 cm) wide. It lies beneath the stomach and is connected to the small intestine at the duodenum (see digestive system).
..... Click the link for more information.
. It tends to counteract the action of insulininsulin,
hormone secreted by the β cells of the islets of Langerhans, specific groups of cells in the pancreas. Insufficiency of insulin in the body results in diabetes. Insulin was one of the first products to be manufactured using genetic engineering.
..... Click the link for more information.
, i.e., it raises the concentration of glucose in the blood. Glucagon was first purified and crystallized in 1955; the amino acid sequence of this 29-amino acid polypeptide (see peptidepeptide,
organic compound composed of amino acids linked together chemically by peptide bonds. The peptide bond always involves a single covalent link between the α-carboxyl (oxygen-bearing carbon) of one amino acid and the amino nitrogen of a second amino acid.
..... Click the link for more information.
) was published in 1956–57. One of the most important actions of glucagon is the promotion of glycogenolysis, i.e., the degradation of glycogenglycogen
, starchlike polysaccharide (see carbohydrate) that is found in the liver and muscles of humans and the higher animals and in the cells of the lower animals. Chemically it is a highly branched condensation polymer of glucose; it is readily hydrolyzed to glucose.
..... Click the link for more information.
 to glucose, in the liver. Glucagon stimulates adenyl cyclase, the enzyme that catalyzes the conversion of adenosine triphosphateadenosine triphosphate
(ATP) , organic compound composed of adenine, the sugar ribose, and three phosphate groups. ATP serves as the major energy source within the cell to drive a number of biological processes such as photosynthesis, muscle contraction, and the synthesis of
..... Click the link for more information.
 to 3′5′-cyclic adenosine monophosphateadenosine monophosphate
(AMP) , organic compound composed of an adenine base, the sugar ribose, and one phosphate unit. AMP is one of the possible products of the hydrolysis of adenosine triphosphate (ATP) and is therefore important in the transfer of chemical energy during
..... Click the link for more information.
 (cyclic AMP).

Glucagon

The protein hormone secreted by the pancreas which 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 sugar in the blood. 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. Glucagon is used in human medicine chiefly in certain diabetic conditions when a dangerously low blood sugar must be rapidly raised. See Carbohydrate metabolism, Glycogen, Hormone, Insulin, Pancreas

glucagon

[′glü·kə‚gän]
(biochemistry)
The protein hormone secreted by α-cells of the pancreas which plays a role in carbohydrate metabolism. Also known as hyperglycemic factor; hyperglycemic glycogenolytic factor.
References in periodicals archive ?
Glucagon works in opposition to insulin, preventing the storage of glucose in fat deposits and the liver, and raising blood sugar levels.
GLP-1 led to a significant reduction (~40%) in glucagon secretion, whereas GIP did not, which suggests that GIP is not as useful in the management of T2DM.
Similarly, weight loss also is seen by blocking glucagon action.
Plasma glucagon, serum insulin, and serum amylase levels in normal and a hyperglycemic macaw.
Ekhlaspour and her colleagues surmised that a closed-loop system comprising a wearable bionic pancreas system that automatically delivers glucagon could reduce the incidence and severity of hypoglycemia when used along with the conventional insulin therapies of multiple daily injection (MDI) or continuous subcutaneous insulin infusion (CSII).
On the other hand, glucagon is secreted by the alpha cells of the pancreatic islets in much the same manner as insulin, except in the opposite direction.
School staff are allowed to volunteer to be trained to administer insulin and/or glucagon.
described iatrogenic NME following intravenous glucagon infusion
Further well-planned studies are needed to elucidate the effects of glucagon like peptide 1 receptor agonists in the treatment of obese individuals without diabetes.
The caregiver presses a small plunger on the bottom of the device to release the glucagon as a puff in the nose, where the glucagon is absorbed in the nasal passages.
El peptido similar al glucagon tipo 1 (GLP-1, por sus siglas en ingles) tiene como funcion principal, potenciar la secrecion de insulina estimulada por glucosa y mejorar la biosintesis de insulina a traves de la induccion de la expresion del gen de insulina (Drucker et al.
STEMC7007 establishes normal beta cell function in diabetic cell populations by producing and secreting insulin and glucagon in invitro cell culture system.