title: Ontogeny of the pancreatic islet parenchymal cells in the rabbit--an immunohistochemical and ultrastructural study with particular regard to the earliest appearance of argyrophil insulin-immunoreactive cells.
abstract: Six early developmental stages of the rabbit pancreas were selected, viz. the embryonic ages 10 days 10 hours, 10 days 18 hours, 11 days 14 hours, 13 days, 15 days, and 18 days. Both non-immunological (histologic-tinctorial features, including argyrophilia, and transmission electron microscopy) and immunohistochemical (the indirect immunofluorescence and/or the peroxidase-anti-peroxidase procedure) methods were used to follow the time-course for the appearance and differentiation of both endocrine (islet) cells and exocrine acinar epithelium. The immunological procedures were, however, limited to the 3 later developmental stages. In the first 3 developmental stages only the dorsal anlage of the pancreas could be found. It was just investigated ultrastructurally. Then, a few parenchymal cells were observed, equipped with secretory granules of endocrine type, indicating that an early differentiation of islet cells had already begun. In the later 3 developmental stages a ventral pancreas anlage was present and at least 2 types of argyrophil islet cells, equipped with secretory granules, were observed. In the pancreas anlage of 13-day-old embryos these early endocrine cells were found to be glucagon-immunoreactive. At the developmental age of 15 days argyrophil insulin-immunoreactive cells were also present, and in the 18-day-old embryos a few somatostatin cells could occasionally be discovered, too. No PP cells were found. Any exocrine acinar differentiation (with zymogen granules) was not observed until at the developmental age of 18 days.
mesh_terms: D000375:Aging; D000818:Animals; D005314:Embryonic and Fetal Development; D005865:Gestational Age; D007150:Immunohistochemistry; D007328:Insulin / Q000032:analysis* / Q000276:immunology; D007515:Islets of Langerhans / Q000166:cytology / Q000196:embryology* / Q000648:ultrastructure; D008854:Microscopy, Electron; D011817:Rabbits; D013194:Staining and Labeling
chemical_list: D007328:Insulin