Target type: biologicalprocess
Any process that activates or increases the frequency, rate or extent of the regulated release of glucagon. [GOC:BHF, GOC:mah]
Positive regulation of glucagon secretion is a complex process that involves the coordinated action of multiple factors, including nutrients, hormones, and neurotransmitters. Glucagon, a peptide hormone produced by alpha cells in the islets of Langerhans in the pancreas, plays a crucial role in regulating blood glucose levels. It acts as a counterregulatory hormone to insulin, raising blood glucose levels by promoting glycogenolysis (breakdown of glycogen to glucose) in the liver and gluconeogenesis (synthesis of glucose from non-carbohydrate sources).
Several factors can stimulate glucagon secretion, including:
1. **Hypoglycemia (low blood glucose):** This is the primary stimulus for glucagon release. When blood glucose levels fall below a certain threshold, the alpha cells sense the decrease and release glucagon to raise blood sugar.
2. **Amino acids:** The presence of amino acids, particularly arginine, in the bloodstream can directly stimulate glucagon secretion. This effect is particularly important during periods of protein digestion and absorption.
3. **Catecholamines:** Epinephrine and norepinephrine, hormones released from the adrenal medulla during stress or exercise, can also stimulate glucagon release. This contributes to the mobilization of energy stores during times of increased metabolic demand.
4. **Glucagon-like peptide-1 (GLP-1):** This incretin hormone, produced by intestinal L cells in response to food intake, can both stimulate insulin release and inhibit glucagon release. However, in the context of hypoglycemia, GLP-1's stimulatory effect on insulin secretion is weaker, allowing for the dominant effect of glucagon release.
5. **Other hormones:** Glucagon release can also be influenced by other hormones like growth hormone, cortisol, and somatostatin.
The precise mechanisms by which these factors stimulate glucagon secretion are complex and involve multiple signaling pathways within the alpha cells. These pathways include:
* **Cyclic AMP (cAMP) pathway:** Hypoglycemia, amino acids, catecholamines, and GLP-1 activate the cAMP pathway, leading to increased intracellular cAMP levels. cAMP activates protein kinase A (PKA), which phosphorylates and activates transcription factors that promote glucagon gene expression.
* **Calcium pathway:** Hypoglycemia and other factors can increase intracellular calcium levels, which in turn activates protein kinase C (PKC). PKC also contributes to glucagon gene expression and secretion.
* **Other signaling pathways:** Other signaling pathways, such as the phosphoinositide 3-kinase (PI3K) pathway, may also play a role in regulating glucagon secretion.
The regulation of glucagon secretion is a tightly controlled process, ensuring that blood glucose levels are maintained within a narrow range. Dysregulation of glucagon secretion can contribute to various metabolic disorders, including diabetes mellitus.
It is important to note that this is a simplified overview of a complex biological process. Further research is needed to fully understand the intricate mechanisms involved in positive regulation of glucagon secretion.'
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Protein | Definition | Taxonomy |
---|---|---|
Free fatty acid receptor 4 | A free fatty acid receptor 4 that is encoded in the genome of human. [PRO:WCB, UniProtKB:Q5NUL3] | Homo sapiens (human) |
Compound | Definition | Classes | Roles |
---|---|---|---|
lauric acid | dodecanoic acid : A straight-chain, twelve-carbon medium-chain saturated fatty acid with strong bactericidal properties; the main fatty acid in coconut oil and palm kernel oil. | medium-chain fatty acid; straight-chain saturated fatty acid | algal metabolite; antibacterial agent; plant metabolite |
12-hydroxy stearic acid | 12-hydroxy stearic acid: structure in first source 12-hydroxyoctadecanoic acid : A hydroxy fatty acid that is stearic acid bearing a hydroxy substituent at position 12. | hydroxyoctadecanoic acid; secondary alcohol | bacterial xenobiotic metabolite; plant metabolite |
16-hydroxypalmitic acid | 16-hydroxyhexadecanoic acid : An omega-hydroxy-long-chain fatty acid that is hexadecanoic acid (also known as palmitic acid) which is substituted at position 16 by a hydroxy group. It is a key monomer of cutin in the plant cuticle. | hydroxypalmitic acid; omega-hydroxy-long-chain fatty acid | plant metabolite |
12-hydroxydodecanoic acid | 12-hydroxylauric acid : A medium-chain fatty acid that is the 12-hydroxylated derivative of lauric acid. | omega-hydroxy-medium-chain fatty acid | human metabolite |
3-hydroxydodecanoic acid | 3-hydroxydodecanoic acid: RN given refers to cpd without isomeric designation 3-hydroxylauric acid : A medium-chain fatty acid that is the 3-hydroxylated derivative of lauric acid; associated with fatty acid metabolic disorders. | 3-hydroxy fatty acid; medium-chain fatty acid | |
ricinoleic acid | ricinoleic acid : A (9Z)-12-hydroxyoctadec-9-enoic acid in which the 12-hydroxy group has R-configuration.. ricinoleic acid: RN given refers to (R-(Z))-isomer; structure in Merck Index, 9th ed, #8005 | (9Z)-12-hydroxyoctadec-9-enoic acid | |
linoleic acid | linoleic acid : An octadecadienoic acid in which the two double bonds are at positions 9 and 12 and have Z (cis) stereochemistry. Linoleic Acid: A doubly unsaturated fatty acid, occurring widely in plant glycosides. It is an essential fatty acid in mammalian nutrition and is used in the biosynthesis of prostaglandins and cell membranes. (From Stedman, 26th ed) | octadecadienoic acid; omega-6 fatty acid | algal metabolite; Daphnia galeata metabolite; plant metabolite |
alpha-linolenic acid | linolenate : A polyunsaturated fatty acid anion obtained by deprotonation of the carboxy group of either alpha- or gamma-linolenic acid. linolenic acid : A two-membered subclass of octadecatrienoic acid comprising the (9Z,12Z,15Z)- and (6Z,9Z,12Z)-isomers. Linolenic acids are nutrients essential to the formation of prostaglandins and are also used in making paints and synthetic resins. | linolenic acid; omega-3 fatty acid | micronutrient; mouse metabolite; nutraceutical |
gw9508 | GW9508: structure in first source | aromatic amine | |
tak-875 | biphenyls | ||
tug-469 | TUG-469: a GPR40 agonist with antidiabetic activity; structure in first source | ||
tug-891 | GPU-028: structure in first source |