Peptide YY
PDB rendering based on 1qbf.
Available structures PDB Ortholog search: PDBe, RCSB List of PDB id codes 2DEZ, 2DF0, 2L60
Identifiers
Symbols	PYY; PYY1
External IDs	OMIM: 600781 MGI: 99924 HomoloGene: 3066 GeneCards: PYY Gene
Gene Ontology Molecular function • hormone activity • neuropeptide hormone activity Cellular component • extracellular region • extracellular space • soluble fraction Biological process • cellular component movement • cytoskeleton organization • G-protein coupled receptor signaling pathway • cell-cell signaling • digestion • feeding behavior • cell proliferation • negative regulation of response to food • eating behavior Sources: Amigo / QuickGO
Orthologs
Species	Human	Mouse
Entrez	5697	217212
Ensembl	ENSG00000131096	ENSMUSG00000017311
UniProt	P10082	Q9EPS2
RefSeq (mRNA)	NM_004160.4	NM_145435.1
RefSeq (protein)	NP_004151.3	NP_663410.1
Location (UCSC)	Chr 17: 42.03 – 42.08 Mb	Chr 11: 101.97 – 101.97 Mb
PubMed search	[1]	[2]
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Peptide YY (PYY) is a short (36-amino acid) protein released by cells in the ileum and colon in response to feeding. In humans it appears to reduce appetite.

It is also known as peptide tyrosine tyrosine or pancreatic peptide YY_3-36.^[1]

Structure[link]

Peptide YY is related to the pancreatic peptide family by having 18 of its 36 amino acids located in the same positions as pancreatic peptide.^[2] There are two major forms of Peptide YY: PYY_1-36 and PYY_3-36 which have PP fold structural motif. However, the most common form of circulating PYY immunoreactivity is PYY_3-36, which binds to the Y2 receptor (Y2R) of the Y family of receptors.^[3] Peptide YY_3-36 (PYY) is a linear polypeptide consisting of 36 amino acids with structural homology to NPY and pancreatic polypeptide.

Release[link]

PYY is found in L cells in the mucosa of gastrointestinal tract, especially in ileum and colon. There is also a small amount of PYY, about 1-10 percent, in esophagus, stomach, duodenum and jejunum.^[4] PYY concentration in the circulation increases postprandially (after food ingestion) and decreases by fasting.^[3] In addition, PYY is produced by a discrete population of neurons in the brainstem, specifically localized to the gigantocellular reticular nucleus of the medulla oblongata.^[5] C. R. Gustavsen et al. had found PYY producing cells located in the islets af Langerhans in rats. They were observed either alone or co-localized with glucagon or PP.^[6]

Function[link]

PYY exerts its action through NPY receptors, inhibits gastric motility and increases water and electrolyte absorption in the colon.^[7] PYY may also suppress pancreatic secretion. It is secreted by the neuroendocrine cells in the ileum and colon in response to a meal, and has been shown to reduce appetite. PYY works by slowing the gastric emptying; hence, it increases efficiency of digestion and nutrient absorption after meal. Research has also indicated that PYY may be useful in removing aluminium accumulated in the brain.

Animal studies[link]

Several studies have shown that acute peripheral administration of PYY_3-36 inhibits feeding of rodents and primates. Some more studies on Y2R-knockout mice have been done, and the result has revealed that there is no anorectic effect on Y2R-knock out mice. This findings indicate that PYY_3-36 has anorectic ( losing appetite) effect, which is suggested to be mediated by Y2R. Some studies have been done to investigate the effect of PYY on mice. Pyy-knock out female mice increase in body weight and fat mass. Pyy-knockout mice, on the other hand, are resistant to obesity but have higher fat mass and lower glucose tolerance when fed with high-fat diet, compare to control mice. Thus PYY also plays very important role in energy homeostasis by balancing the food intake.^[3]

Relevance to obesity[link]

Leptin also reduces appetite in response to feeding, but obese people develop a resistance to leptin. It has also been known that obese people secrete less PYY than non-obese people.^[8] On the other hand, attempts to use PYY directly as a weight-loss drug have met with some success. Researchers noted that caloric intake during a buffet lunch offered two hours after the infusion of PYY was decreased by 30 percent in obese subjects (P<0.001) and 31 percent in lean subjects (P<0.001).^[9]

While some studies have shown that obese persons have lower circulating level of PYY postprandially, other studies have reported that obese people have normal sensitivity to anoretic effect of PYY_3-36. Thus, reduction in PYY secretion may not be one of the causes of obesity. However, the anoretic effect of PYY could possibly be a future obesity drug.^[3]

Research done in 2006 showed that consumption of protein boosts PYY levels, therefore some benefit was observed in experimental subjects in terms of reducing hunger and promoting weight loss.^[10] This would help explain the weight-loss experienced with high-protein diets.

See also[link]

• Ghrelin
• Leptin

References[link]

Further reading[link]

External links[link]

• Peptide+YY at the US National Library of Medicine Medical Subject Headings (MeSH)

v t e PDB gallery 1qbf: NMR SOLUTION STRUCTURE OF PORCINE PEPTIDE YY   1ru5: Solution structure of porcine peptide YY (pPYY)   1ruu: Solution structure of porcine peptide YY (pPYY) bound to DPC micelles   2dez: Structure of human PYY   2df0: Solution structure of human PYY3-36