Vasoactive Intestinal Peptide Unit Converter

Vasoactive intestinal peptide (VIP) is a 28-amino-acid neuropeptide that acts as both a neurotransmitter and a hormone. It belongs to the secretin/glucagon superfamily and was first isolated from the small intestine in 1970.

VIP regulates a wide range of processes including blood vessel dilation, gut motility, water secretion into the intestine, immune function, and circadian rhythm. It works through two receptors (VPAC1 and VPAC2) found on cells throughout the body.

VIP has an extremely short half-life of less than one minute in the bloodstream. The liver rapidly clears it, so circulating levels are normally very low. Measuring VIP in blood is primarily used to help diagnose VIP-secreting tumors (VIPomas) in patients with unexplained chronic watery diarrhea.

VIP is produced by nerve cells throughout the gastrointestinal tract (the richest source), the brain (especially the suprachiasmatic nucleus and hypothalamus), the pancreas, lungs, adrenal glands, and certain immune cells.