PYY, peptide tyrosine tyrosine PYY or pancreatic peptide YY3-36 Peptide YY (PYY) is a peptide that in humans is encoded by the PPY gene. Peptide YY is a short (36-amino acid) peptide released by cells in the ileum and colon in response to feeding. In the blood, gut, and other elements of periphery, PYY acts to reduce appetite; but when injected directly into the central nervous system, PYY is orexigenic, i.e., it increases appetite. Peptide YY can be produced as the result of enzymatic breakdown of crude fish proteins and ingested as a food product with hunger reducing attributes. Peptide YY binds to the Y2 receptor (Y2R) of the Y family of receptors. PYY exerts its action through NPY receptors; it inhibits gastric motility and increases water and electrolyte absorption in the colon. The biological action of PYY involves a wide range of digestive functions, which include regulation of insulin secretion, inhibition of gastric acid secretion, gastric emptying, mouth-to-cecum transit time, and gallbladder contraction in the cephalic phase in humans, with the latter functions being carried out by the PYY1–36 isoform. PYY concentrations rise within 15–30 min after meal ingestion and appear to be initiated by an indirect neuronal reflex. PYY secretion is stimulated by different macronutrients and is partially related to the calories ingested. Fat is the most potent stimulator of PYY release in humans. Protein-rich diets cause a great increase in PYY levels in healthy and obese humans. In obese subjects, fat- and carbohydrate-induced PYY secretion is significantly reduced compared to lean subjects, whereas the response induced by protein increased.
Posted on: Tue, 02 Sep 2014 18:20:27 +0000
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