Functional subdivision of islets of Langerhans and possible role of D cells.
Immunocytochemical examination of the islets of Langerhans in various animal species, including man, indicates that insulin-producing cells (B cells), glucagon-producing cells (A cells), and cells producing somatostatin or a somatostatin-like peptide (D cells) are not randomly arranged within the islet. Whenever A cells are found in the islet--i.e., mostly in its peripheral part--they are accompanied by D cells. However, most B cells, which occupy a central position, are in contact only with other B cells. In view of the inhibitory effect of somatostatin on both insulin and glucagon secretion, it is suggested that the arrangement of A, B and D cells is important to the normal and pathological functioning of the islet.
D000818:Animals; D005934:Glucagon / Q000037:antagonists & inhibitors / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000378:metabolism; D007329:Insulin Antagonists; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000166:cytology* / Q000378:metabolism / Q000502:physiology; D013004:Somatostatin / Q000378:metabolism / Q000502:physiology*
D007328:Insulin; D007329:Insulin Antagonists; D013004:Somatostatin; D005934:Glucagon