title: Proliferation, senescence, and neoplastic progression of beta cells in hyperplasic pancreatic islets.
abstract: Three different cases of pancreatic beta cell hyperplasia in mice are accompanied by an increase in a subclass of cells expressing tyrosine hydroxylase (TH), a neuronal enzyme. In the nontumorigenic cases of islet growth during normal pregnancy and in the obese mutant mouse, the TH-insulin cells do not divide, in contrast to the "insulin-only" cells. In later stages the number of proliferating insulin-only cells decreases concomitant with an increase in the number of nondividing TH-insulin cells, suggesting that the TH-insulin cells are on a pathway to senescence. In the presence of an oncoprotein the TH-insulin cells are able to proliferate. The proliferation of this cell type may represent an escape from the senescence pathway and progression to immortal tumor cells.
mesh_terms: D000818:Animals; D002455:Cell Division; D002470:Cell Survival; D002471:Cell Transformation, Neoplastic / Q000473:pathology*; D005260:Female; D006965:Hyperplasia; D007150:Immunohistochemistry; D007328:Insulin / Q000096:biosynthesis; D007340:Insulinoma / Q000473:pathology; D007515:Islets of Langerhans / Q000201:enzymology / Q000473:pathology*; D051379:Mice; D008820:Mice, Obese; D008822:Mice, Transgenic; D008938:Mitosis; D009765:Obesity / Q000201:enzymology; D009857:Oncogenes; D010190:Pancreatic Neoplasms / Q000473:pathology; D011247:Pregnancy / Q000378:metabolism; D014446:Tyrosine 3-Monooxygenase / Q000096:biosynthesis / Q000378:metabolism
chemical_list: D007328:Insulin; D014446:Tyrosine 3-Monooxygenase