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| Pancreatic polypeptide | |||||||
|---|---|---|---|---|---|---|---|
 | |||||||
| Identifiers | |||||||
| Symbol | PPY | ||||||
| NCBI gene | 5539 | ||||||
| HGNC | 9327 | ||||||
| OMIM | 167780 | ||||||
| RefSeq | NM_002722 | ||||||
| UniProt | P01298 | ||||||
| Other data | |||||||
| Locus | Chr. 17p11.1-qter | ||||||
| |||||||
Pancreatic polypeptide (PP) is apolypeptide secreted byPP cells in theendocrine pancreas. It is ahormone and it regulatespancreatic secretion activities, and also impactsliverglycogen storage and gastrointestinal secretion. Its secretion may be impacted by certainendocrine tumours.
ThePPY gene encodes an unusually short protein precursor of 95 amino acids in length.[1] This precursor is cleaved to produce thesignal peptide, the pancreatic polypeptide, thepancreatic icosapeptide, and a 5- to 7- amino-acid oligopeptide.[1]
Pancreatic polypeptide consists of 36amino acids.[2][3] It has a molecular weight about 4200Da.[2] It has a similar structure toneuropeptide Y.[3]
Pancreatic polypeptide is synthesised and secreted byPP cells (also known as gamma cells or F cells) of thepancreatic islets of thepancreas.[3][4] These are found predominantly in thehead of the pancreas.[citation needed]
Pancreatic polypeptide regulatespancreatic secretion activities by both endocrine and exocrine tissues. It also affects hepaticglycogen levels and gastrointestinal secretions.
Its secretion in humans is increased after a protein meal,fasting, exercise, and acutehypoglycaemia, and is decreased bysomatostatin and intravenousglucose.
Plasma pancreatic polypeptide has been shown to be reduced in conditions associated with increased food intake and elevated inanorexia nervosa. In addition, peripheral administration of polypeptide has been shown to decrease food intake in rodents.[5] Pancreatic polypeptide inhibits pancreatic secretion of fluid,bicarbonate, anddigestive enzymes.[3] It also stimulatesgastric acid secretion.[3] It is the antagonist ofcholecystokinin and opposes pancreatic secretion stimulated by cholecystokinin.[3] It may stimulate themigrating motor complex, synergistic withmotilin.[3]
On fasting, pancreatic polypeptide concentration is 80 pg/ml; after the meal, it rises up from 8 to 10 times more; glucose and fats also induce PP's level increase, but on parenteral introduction of those substances, the level of hormones doesn't change. The administration ofatropine, thevagotomy, blocks pancreatic polypeptide secretion after meals. The excitation of thevagus nerve, the administration ofgastrin,secretin or cholecystokinin induce PP secretion.
The secretion of pancreatic polypeptide may be increased by pancreatic tumours (insulin,glucagon), byVerner-Morrison syndrome, and bygastrinoma.