Pancreatic polypeptide

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
Pancreatic polypeptide
Pancreatic hormone 1TZ5.png
Identifiers
SymbolPPY
NCBI gene5539
HGNC9327
OMIM167780
RefSeqNM_002722
UniProtP01298
Other data
LocusChr. 17 p11.1-qter
IHC for Pancreatic polypeptide in a mouse pancreas, 200×

Pancreatic polypeptide (PP) is a polypeptide secreted by PP cells in the endocrine pancreas. It regulates pancreatic secretion activities, and also impact liver glycogen storage and gastrointestinal secretion. Its secretion may be impacted by certain endocrine tumours.

Gene[edit]

The PPY gene encodes an unusually short protein precursor.[1] This precursor is cleaved to produce pancreatic polypeptide, pancreatic icosapeptide, and a 5- to 7- amino-acid oligopeptide.[1]

Structure[edit]

Pancreatic polypeptide consists of 36 amino acids.[2][3] It has a molecular weight about 4200 Da.[2] It has a similar structure to neuropeptide Y.[3]

Synthesis[edit]

Pancreatic polypeptide is synthesised and secreted by PP cells (also known as gamma cells or F cells) of the pancreatic islets of the pancreas.[3][4] These are found predominantly in the head of the pancreas.[citation needed]

Function[edit]

Pancreatic polypeptide regulates pancreatic secretion activities by both endocrine and exocrine tissues. It also affects hepatic glycogen levels and gastrointestinal secretions.

Its secretion in humans is increased after a protein meal, fasting, exercise, and acute hypoglycaemia, and is decreased by somatostatin and intravenous glucose.

Plasma pancreatic polypeptide has been shown to be reduced in conditions associated with increased food intake and elevated in anorexia 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, and digestive enzymes.[3] It also stimulates gastric acid secretion.[3] It is the antagonist of cholecystokinin and opposes pancreatic secretion stimulated by cholecystokinin.[3] It may stimulate the migrating motor complex, synergistic with motilin.[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 of atropine, the vagotomy, blocks pancreatic polypeptide secretion after meals. The excitation of the vagus nerve, the administration of gastrin, secretin or cholecystokinin induce PP secretion.

Clinical significance[edit]

The secretion of pancreatic polypeptide may be increased by pancreatic tumours (insulin, glucagon), by Verner-Morrison syndrome, and by gastrinomas.

See also[edit]

References[edit]

  1. ^ a b Boel, E.; Schwartz, T. W.; Norris, K. E.; Fiil, N. P. (April 1984). "A cDNA encoding a small common precursor for human pancreatic polypeptide and pancreatic icosapeptide". EMBO Journal. 3 (4): 909–912. doi:10.1002/j.1460-2075.1984.tb01904.x. PMC 557446. PMID 6373251.
  2. ^ a b Lonovics J, Devitt P, Watson LC, Rayford PL, Thompson JC (Oct 1981). "Pancreatic polypeptide". Arch. Surg. 116 (10): 1256–64. doi:10.1001/archsurg.1981.01380220010002. PMID 7025798.
  3. ^ a b c d e f g Washabau, Robert J. (2013). "Chapter 1 - Integration of Gastrointestinal Function". Canine and Feline Gastroenterology. Saunders. pp. 1–31. doi:10.1016/B978-1-4160-3661-6.00001-8. ISBN 978-1-4160-3661-6.
  4. ^ Cozzi, Bruno; Huggenberger, Stefan; Oelschläger, Helmut (2017-01-01). "Chapter 7 - Body Control: The Endocrine System and the Peripheral Nervous System". Anatomy of Dolphins. Academic Press. pp. 305–338. doi:10.1016/B978-0-12-407229-9.00007-5. ISBN 978-0-12-407229-9.CS1 maint: date and year (link)
  5. ^ Batterham, RL; Le Roux, CW; Cohen, MA; Park, AJ; Ellis, SM; Patterson, M; Frost, GS; Ghatei, MA; Bloom, SR (Aug 2003). "Pancreatic polypeptide reduces appetite and food intake in humans". The Journal of Clinical Endocrinology and Metabolism. 88 (8): 3989–92. doi:10.1210/jc.2003-030630. PMID 12915697.

External links[edit]