Glucagon/gastric inhibitory polypeptide/secretin/vasoactive intestinal peptide hormones are a family of evolutionarily related

peptide hormone Peptide hormones or protein hormones are hormones whose molecules are peptide, or proteins, respectively. The latter have longer amino acid chain lengths than the former. These hormones have an effect on the endocrine system of animals, including h ...

s that regulate activity of G-protein-coupled receptors from the

secretin receptor family Secretin family receptor proteins, also known as Family B or family 2 of G-protein coupled receptors are regulated by peptide hormones from the glucagon hormone family. The family is different from adhesion G protein-coupled receptors. The secr ...

. A number of polypeptidic hormones, mainly expressed in the

intestine The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans an ...

or the

pancreas The pancreas is an organ of the digestive system and endocrine system of vertebrates. In humans, it is located in the abdomen behind the stomach and functions as a gland. The pancreas is a mixed or heterocrine gland, i.e. it has both an ...

, belong to a group of these structurally related peptides. One such hormone,

glucagon Glucagon is a peptide hormone, produced by alpha cells of the pancreas. It raises concentration of glucose and fatty acids in the bloodstream, and is considered to be the main catabolic hormone of the body. It is also used as a medication to tre ...

, is widely distributed and produced in the

alpha-cell Alpha cells (α cells) are endocrine cells that are found in the Islets of Langerhans in the pancreas. Alpha cells secrete the peptide hormone glucagon in order to increase glucose levels in the blood stream. Discovery Islets of Langerhans were ...

s of pancreatic islets. It affects

glucose Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, u ...

metabolism Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run ...

in the

liver The liver is a major organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the synthesis of proteins and biochemicals necessary for digestion and growth. In humans, it i ...

by inhibiting glycogen synthesis, stimulating

glycogenolysis Glycogenolysis is the breakdown of glycogen (n) to glucose-1-phosphate and glycogen (n-1). Glycogen branches are catabolized by the sequential removal of glucose monomers via phosphorolysis, by the enzyme glycogen phosphorylase. Mechanism T ...

and enhancing

gluconeogenesis Gluconeogenesis (GNG) is a metabolic pathway that results in the generation of glucose from certain non- carbohydrate carbon substrates. It is a ubiquitous process, present in plants, animals, fungi, bacteria, and other microorganisms. In verteb ...

. It also increases mobilisation of glucose, free

fatty acid In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, f ...

s, and

ketone bodies Ketone bodies are water-soluble molecules that contain the ketone groups produced from fatty acids by the liver ( ketogenesis). Ketone bodies are readily transported into tissues outside the liver, where they are converted into acetyl-CoA (acet ...

, which are metabolites produced in excess in

diabetes mellitus Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ...

. Glucagon is produced, like other peptide hormones, as part of a larger precursor (

preproglucagon Proglucagon is a protein that is cleaved from preproglucagon. Preproglucagon in humans is encoded by the ''GCG'' gene. Proglucagon is a precursor of glucagon, and several other components. It is generated in the alpha cells of the pancreas and in ...

), which is cleaved to produce glucagon, glucagon-like protein I, glucagon-like protein II, and glicentin. The structure of glucagon itself is fully conserved in all mammalian species in which it has been studied. Other members of the structurally similar group include

secretin Secretin is a hormone that regulates water homeostasis throughout the body and influences the environment of the duodenum by regulating secretions in the stomach, pancreas, and liver. It is a peptide hormone produced in the S cells of the du ...

gastric inhibitory peptide Glucose-dependent insulinotropic polypeptide (GIP), also known as Gastric inhibitory polypeptide or gastric inhibitory peptide (also abbreviated as GIP), is an inhibiting hormone of the secretin family of hormones. While it is a weak inhibitor ...

vasoactive intestinal peptide Vasoactive intestinal peptide, also known as vasoactive intestinal polypeptide or VIP, is a peptide hormone that is vasoactive in the intestine. VIP is a peptide of 28 amino acid residues that belongs to a glucagon/secretin superfamily, the lig ...

, prealbumin, peptide HI-27, and growth hormone releasing factor.

Human hormones from this family

ADCYAP1; GCG; GHRH; GIP; SCT;

VIP A very important person or personage (VIP or V.I.P.) is a person who is accorded special privileges due to their high social status, influence or importance. The term was not common until sometime after World War 2 by RAF pilots. Examples inc ...

;

References

{{DEFAULTSORT:Secretin Family Protein domains Peripheral membrane proteins Peptide hormones Hormones of the digestive system Hormones of glucose metabolism