Glucagon/GIP/secretin/VIP hormones are a family of evolutionarily related

Protein family

A protein family is a group of evolutionarily-related proteins, and is often nearly synonymous with gene family. The term protein family should not be confused with family as it is used in taxonomy....

 peptide hormone

Peptide hormone

Peptide hormones are a class of peptides that are secreted into the blood stream and have endocrine functions in living animals.Like other proteins, peptide hormones are synthesized in cells from amino acids according to an mRNA template, which is itself synthesized from a DNA template inside the...

s that regulate activity of G-protein coupled receptors from secretin receptor family

Secretin receptor family

Secretin family of 7 transmembrane receptors is a family of evolutionarily related proteins.This family is known as Family B, the secretin-receptor family or family 2 of the G-protein-coupled receptors...

.

A number of polypeptidic hormones, mainly expressed in the intestine

Intestine

In human anatomy, the intestine is the segment of the alimentary canal extending from the pyloric sphincter of the stomach to the anus and, in humans and other mammals, consists of two segments, the small intestine and the large intestine...

 or the pancreas

Pancreas

The pancreas is a gland organ in the digestive and endocrine system of vertebrates. It is both an endocrine gland producing several important hormones, including insulin, glucagon, and somatostatin, as well as a digestive organ, secreting pancreatic juice containing digestive enzymes that assist...

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

Glucagon

Glucagon, a hormone secreted by the pancreas, raises blood glucose levels. Its effect is opposite that of insulin, which lowers blood glucose levels. The pancreas releases glucagon when blood sugar levels fall too low. Glucagon causes the liver to convert stored glycogen into glucose, which is...

 is widely distributed and produced in the alpha-cells of pancreatic islets. It affects glucose

Glucose

Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...

 metabolism

Metabolism

Metabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...

 in the liver

Liver

The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...

 by inhibiting glycogen synthesis, stimulating glycogenolysis and enchancing gluconeogenesis. It also increases mobilisation of glucose, free fatty acid

Fatty acid

In chemistry, especially biochemistry, a fatty acid is a carboxylic acid with a long unbranched aliphatic tail , which is either saturated or unsaturated. Most naturally occurring fatty acids have a chain of an even number of carbon atoms, from 4 to 28. Fatty acids are usually derived from...

s and ketone bodies

Ketone bodies

Ketone bodies are three water-soluble compounds that are produced as by-products when fatty acids are broken down for energy in the liver and kidney. They are used as a source of energy in the heart and brain. In the brain, they are a vital source of energy during fasting...

, which are metabolites produced in excess in diabetes mellitus

Diabetes mellitus

Diabetes mellitus, often simply referred to as diabetes, is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced...

. Glucagon is produced, like other peptide hormones, as part of a larger precursor (preproglucagon), which is cleaved to produce glucagon, glucagon-like protein I and glucagon-like protein II. 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 glicentin precursor, secretin

Secretin

Secretin is a hormone that controls the secretions into the duodenum, and also separately, water homeostasis throughout the body. It is produced in the S cells of the duodenum in the crypts of Lieberkühn...

, gastric inhibitory peptide, vasoactive intestinal peptide

Vasoactive intestinal peptide

Vasoactive intestinal peptide also known as the vasoactive intestinal polypeptide or VIP is a peptide hormone containing 29 amino acid residues that is produced in many tissues of vertebrates including the gut, pancreas and suprachiasmatic nuclei of the hypothalamus in the brain...

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

Human hormones from this family

ADCYAP1; GCG

Glucagon

Glucagon, a hormone secreted by the pancreas, raises blood glucose levels. Its effect is opposite that of insulin, which lowers blood glucose levels. The pancreas releases glucagon when blood sugar levels fall too low. Glucagon causes the liver to convert stored glycogen into glucose, which is...

; GHRH; GIP; SCT; VIP

Vasoactive intestinal peptide

Vasoactive intestinal peptide also known as the vasoactive intestinal polypeptide or VIP is a peptide hormone containing 29 amino acid residues that is produced in many tissues of vertebrates including the gut, pancreas and suprachiasmatic nuclei of the hypothalamus in the brain...

;