Enteroendocrine cells are specialized endocrine cells of the gastrointestinal tract and pancreas. They produce in response to various stimuli gastrointestinal hormones or peptides and release them into the bloodstream for systemic effect, diffuse them as local messengers, or transmit them to the enteric nervous system to active nervous responses. Enteroendocrine cells of the intestine are the most numerous endocrine cells of the body. In a sense they are known to act as chemoreceptors, initiating digestive actions and detecting harmful substances and initiating protective responses. Enteroendocrine cells are located in the stomach, in the intestine and in the pancreas.
Intestinal enteroendocrine cells 
Intestinal enteroendocrine cells are not clustered together but spread as single cells throughout the intestinal tract. K-cells and L-cells secrete respectively the incretins gastric inhibitory peptide and glucagon-like peptide-1. Enterochromaffin cells are enteroendocrine and neuroendocrine cells with a close similarity to adrenomedullary chromaffin cells secreting serotonin.
Other hormones secreted include somatostatin, motilin, cholecystokinin, neurotensin, vasoactive intestinal peptide, and enteroglucagon.
Gastric enteroendocrine cells 
Gastric enteroendocrine cells are found at stomach glands, mostly at their base. The G cells secrete gastrin, post-ganglionic fibers of the vagus nerve can release gastrin-releasing peptide during parasympathetic stimulation to stimulate secretion. Enterochromaffin-like cells are enteroendocrine and neuroendocrine cells also known for their similarity to chromaffin cells secreting histamine, which gastrin stimulates.
Other hormones produced include cholecystokinin, somatostatin, vasoactive intestinal peptide, substance P, alpha and gamma-endorphin.
Pancreatic enteroendocrine cells 
Pancreatic enteroendocrine cells are located in the islets of Langerhans and produce most importantly the hormones insulin and glucagon. The autonomous nervous system strongly regulates their secretion, with parasympathetic stimulation stimulating insulin secretion and inhibiting glucagon secretion and sympathetic stimulation having opposite effect. 
Other hormones produced include somatostatin, pancreatic polypeptide, amylin and ghrelin.
Rare and slow growing carcinoid and non-carcinoid tumors develop from these cells. When a tumor arises it has the capacity to secrete large volumes of hormones.
See also 
- ^ Rehfeld, Jens F. The New Biology of Gastrointestinal Hormones. Physiol. Rev. 78: 1087–1108, 1998
- ^ a b Solcia, E; Capella, C; Buffa, R; Usellini, L; Fiocca, R; Frigerio, B; Tenti, P; Sessa, F (1981). "The diffuse endocrine-paracrine system of the gut in health and disease: ultrastructural features.". Scandinavian journal of gastroenterology. Supplement 70: 25–36. PMID 6118945.
- ^ Ahlman, H; Nilsson, (2001). "The gut as the largest endocrine organ in the body.". Annals of oncology : official journal of the European Society for Medical Oncology / ESMO. 12 Suppl 2: S63–8. PMID 11762354.
- ^ Schonhoff, SE; Giel-Moloney, M; Leiter, AB (2004 Jun). "Minireview: Development and differentiation of gut endocrine cells.". Endocrinology 145 (6): 2639–44. PMID 15044355.
- ^ Moran, G. W.; Leslie, F. C.; Levison, S. E.; McLaughlin, J. T. (1 July 2008). "Review: Enteroendocrine cells: Neglected players in gastrointestinal disorders?". Therapeutic Advances in Gastroenterology 1 (1): 51–60. doi:10.1177/1756283X08093943.
- ^ Sternini, C; Anselmi, L; Rozengurt, E (2008 Feb). "Enteroendocrine cells: a site of 'taste' in gastrointestinal chemosensing.". Current opinion in endocrinology, diabetes, and obesity 15 (1): 73–8. PMID 18185066.
- ^ Sternini, C (2007 Feb). "Taste receptors in the gastrointestinal tract. IV. Functional implications of bitter taste receptors in gastrointestinal chemosensing.". American journal of physiology. Gastrointestinal and liver physiology 292 (2): G457–61. PMID 17095755.
- ^ Sternini, Catia; Anselmi, Laura; Rozengurt, Enrique (1 February 2008). "Enteroendocrine cells: a site of ‘taste’ in gastrointestinal chemosensing". Current Opinion in Endocrinology, Diabetes and Obesity 15 (1): 73–78. doi:10.1097/MED.0b013e3282f43a73.
- ^ a b Krause, WJ; Yamada, J; Cutts, JH (1985 Jun). "Quantitative distribution of enteroendocrine cells in the gastrointestinal tract of the adult opossum, Didelphis virginiana.". Journal of anatomy. 140 ( Pt 4): 591–605. PMID 4077699.
- ^ Zverkov, IV; Vinogradov, VA; Smagin, VG (1983 Oct). "Endorphin-containing cells in the gastric antral mucosa in duodenal ulcer.". Biulleten' eksperimental'noi biologii i meditsiny 96 (10): 32–4. PMID 6194833.
- ^ Kiba, T (2004 Aug). "Relationships between the autonomic nervous system and the pancreas including regulation of regeneration and apoptosis: recent developments.". Pancreas 29 (2): e51–8. PMID 15257115.
- ^ Warner, RR (2005 May). "Enteroendocrine tumors other than carcinoid: a review of clinically significant advances.". Gastroenterology 128 (6): 1668–84. PMID 15887158.
External links