Patterns of calcium localization in pancreatic endocrine cells.

摘要: Subcellular calcium localization in the dndocrine cells of rat pancreas was studied by pyroantimonate precipitation technique. Calcium-containing electron-dense deposits endocrine were mostly found within secretory granules and along plasma membrane, but their pattern distribution A-, B- D-cells displayed qualitative quantitative differences. In B-cells, numerous contained located halo surrounding granule core. A-cells, only few precipitates halo, whereas D-cells, situated dense core granules. Deposits membrane occurred generally on outer leaflet inner that A-cells. islets incubated at a high glucose concentration or presence ionophore A23187, number beta containing significantly increased. By contrast, observed B-cells calcium-deprived medium enriched with EGTA. These findings indicate that: varies different islet cell types; represent one major stores intracellular calcium; this store undergoes changes conditions which alter insulin release.