Vasoactive intestinal polypeptide (VIP) is a 28-amino acid peptide hormone. It is a member of the glucagon/secretin superfamily of peptides, which are known to play a role in a variety of biological processes, including digestion, circulation, and respiration.
The amino acid sequence of VIP is as follows:
H-Ser-Asp-Asn-Thr-Phe-Val-Ser-Glu-Leu-Ser-Asp-Leu-Ser-Met-Ser-Asn-Leu-Glu-Leu-Asn-Leu-Leu-Leu-Gln-Ser-Leu-Leu-Lys-Asn-Leu-OH
VIP is produced by specialized cells in the digestive system, nervous system, and other tissues throughout the body. It is released into the bloodstream in response to a variety of stimuli, including food intake, nerve stimulation, hormonal signals, and inflammation.
Once in the bloodstream, VIP binds to specific receptors on the surface of cells. These receptors are called VIP receptors. VIP receptors are found on a variety of cells throughout the body, including smooth muscle cells, blood vessel cells, and immune cells.
When VIP binds to its receptor, it activates a series of signaling pathways that lead to a variety of cellular responses. These responses include:
- Relaxation of smooth muscle
- Increased blood flow
- Secretion of water and electrolytes
- Inhibition of gastric acid secretion
- Release of hormones from the pituitary gland and hypothalamus
- Modulation of immune function
The specific effects of VIP depend on the type of cell that it binds to and the signaling pathways that it activates.
VIP is a pleiotropic hormone, meaning that it has a wide range of biological effects. This is due to the fact that VIP receptors are found on a variety of cells throughout the body.
VIP is a relatively small peptide, but its structure is complex and important for its biological activity. The first 22 amino acids of VIP are essential for its receptor binding and biological activity. The remaining 6 amino acids are thought to play a role in VIP’s stability and metabolism.
VIP is a water-soluble peptide, which means that it can dissolve in water. This is important for its ability to circulate in the bloodstream and reach its target cells.
VIP is also relatively stable in human plasma, meaning that it can remain active for several hours after it is released into the bloodstream. This is important for its ability to exert its biological effects over a period of time.
VIP is a versatile and important peptide hormone with a wide range of biological effects. It is produced by specialized cells in the digestive system, nervous system, and other tissues throughout the body. VIP is released into the bloodstream in response to a variety of stimuli, and it binds to specific receptors on the surface of cells to exert its effects. VIP is a pleiotropic hormone, meaning that it has a wide range of biological effects, due to the fact that VIP receptors are found on a variety of cells throughout the body. VIP is also a relatively small and stable peptide, which is important for its ability to circulate in the bloodstream and reach its target cells.
