The role of PYY in feeding regulation

Peptide YY (PYY), a 36-amino-acid peptide, is secreted primarily from L-cells residing in the intestinal mucosa of the ileum and large intestine. PYY, which belongs to a family of peptides including neuropeptide Y (NPY) and pancreatic polypeptide, is released into the circulation as PYY1–36 and PYY3–36; the latter is the major form of PYY in gut mucosal endocrine cells and throughout the circulation. Plasma PYY levels begin to rise within 15 min after starting to eat and plateau within ∼ 90 min, remaining elevated for up to 6 h. Exogenous administration of PYY3–36 reduces energy intake and body weight in both humans and animals. Via Y2 receptors, the satiety signal mediated by PYY inhibits NPY neurons and activates pro-opiomelanocortin neurons within the hypothalamic arcuate nucleus. Peripheral PYY3–36 binds Y2 receptors on vagal afferent terminals to transmit the satiety signal to the brain. PYY3–36 may have therapeutic potential in human obesity.