Glucagon stimulates insulin secretion

Glucagon, also called glucagon or anti-insulin, is a hormone that increases blood sugar levels. Its effect is exactly opposite to that of insulin. Glucagon can promote the secretion of metabolic hormones. It can promote glycogenolysis and gluconeogenesis, which can significantly increase blood sugar. In the normal treatment process, it is also often used in some treatments. It can promote the decomposition of fat and the oxidation of fatty acids.

Basic Information

In 1953, it was separated and precipitated to obtain crystals. It is a single-chain peptide (molecular weight of about 3500) composed of 29 amino acid residues starting from the N-terminal histidine and ending at the C-terminal threonine. It does not have SS bonds in the molecule, which is completely different from insulin.

The structure of this compound has been confirmed by recent chemical synthesis. The initial process of glucagon's action is to specifically bind to receptors on the cell membrane of target cells, activate adenylate cyclase, and cyclic AMP becomes the second messenger to activate phosphorylase and promote glycogenolysis.

Main Function

In contrast to insulin, glucagon is a catabolism hormone. Glucagon has a strong effect in promoting glycogenolysis and gluconeogenesis, which significantly increases blood sugar. 1 mol/L of the hormone can quickly break down 3×106 mol/L of glucose from glycogen. Glucagon activates the phosphorylase of liver cells through the cAMP-PK system, accelerating glycogenolysis.

Gluconeogenesis is enhanced because hormones accelerate the entry of amino acids into liver cells and activate enzyme systems involved in the gluconeogenesis process. Glucagon can also activate lipase and promote fat decomposition, while at the same time enhancing fatty acid oxidation and increasing ketone body production. The target organ for glucagon to produce the above metabolic effects is the liver. These effects disappear if the liver is removed or the blood flow to the liver is blocked.

In addition, glucagon can promote the secretion of insulin and somatostatin. Pharmacological doses of glucagon can increase the cAMp content in myocardial cells and enhance myocardial contraction.

Main Application

Glucagon is a hormone that promotes metabolism. It has a strong effect in promoting liver glycogenolysis and gluconeogenesis, causing a significant increase in blood sugar; it promotes fat decomposition and fatty acid oxidation; it accelerates the entry of amino acids into liver cells, providing raw materials for gluconeogenesis.

Blood glucose concentration is also the main factor regulating glucagon secretion. When blood sugar decreases, glucagon secretion increases, and vice versa. Insulin can indirectly promote glucagon secretion by lowering blood sugar, and can also directly act on adjacent A cells in a paracrine manner to inhibit their secretion. The sympathetic nerves promote glucagon secretion, while the vagus nerve inhibits it.