endocrine/exocrine glands
• with Notch activation, about 10% of islets have EGFP-positive cells not expressing chromogranin A (ie. non-endocrine cells); most of these cells are duct cells or in small intraislet ductules at ages P2 to 1 year
• no EGFP-labeled cells express amylase, indicating they are not of acinar lineage
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• most islets are histologically indistinguishable from normal littermates, but some cells in the center of islets stain for hormones normally restricted to the islet periphery but not found in the core (glucagon, somatostatin, PP) whereas in normal islets, insulin staining is uniform in the core; this change in distribution is seen in most islets in 2-day old to 1yr old animals but total numbers of non-insulin expressing cells are not significantly changed
• non-insulin expressing endocrine cells in the islet cores do not coexpress insulin or MafA, suggesting they do not have properties of mature beta cells
• about 1-2% of EGFP-labeled cells are associated with large dilated cystic structures lined with cuboidal cell; large EGFP-expressing ducts are sometimes associated with islets and small intraislet ductiles within an adjacent islet
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homeostasis/metabolism
N |
• mice are normoglycemic with normal glucose tolerance
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