title: Histology and cytology of the islets of Langerhans in the Mongolian gerbil (Meriones unguiculatus).
abstract: The histology and cell types of the islets of Langerhans were studies in the Mongolian gerbil during post-natal development using granule stains, fluorescence methods and electron microscopy. Relative islet volume, islet size distribution, islet-duct association, islet-fat association, alpha- and D cell populations and the size distribution of secretion granules in islet cells were quantified. In adult gerbils islets have an elliptical profile enclosed by a thin collagenous capsule, a central core of beta-cells, a peripheral shell of alpha-cells and an incomplete layer of D cells between. In animals of 1 week or less, islets lack a capsule, are poorly vascularized and not innervated, though alpha, beta- and D cells are present. alpha-Cells exhibit green fluorescence during these early stages that disappears when adrenergic nerve fibres grow into the islets. Electron microscopy shows a fourth (unidentified) granular islet cell type, and small granular cells, that probably correspond to intensely fluorescent cells, were found within islets and neuroinsular complexes.
mesh_terms: D000367:Age Factors; D000818:Animals; D004298:Dopamine / Q000032:analysis; D005849:Gerbillinae / Q000033:anatomy & histology*; D007515:Islets of Langerhans / Q000166:cytology* / Q000254:growth & development / Q000648:ultrastructure; D008854:Microscopy, Electron; D012701:Serotonin / Q000032:analysis; D013194:Staining and Labeling
chemical_list: D012701:Serotonin; D004298:Dopamine