Sequential determination of calcium distribution in B cells at the various phases of glucose-induced insulin secretion
| Autor: | Rodolfo E. Hernández, M.C. Semino, Juan José Gagliardino, Oscar R. Rebolledo, C.L.A. Gómez Dumm |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 1984 |
| Předmět: |
Blood Glucose
Pyroantimonate Endocrinology Diabetes and Metabolism medicine.medical_treatment chemistry.chemical_element Calcium Biology Cytoplasmic Granules Islets of Langerhans chemistry.chemical_compound symbols.namesake Culture Techniques Internal Medicine medicine Animals Insulin Secretion Pancreas perfusion Insulin secretion Cell Membrane Rats Inbred Strains Golgi apparatus Rats EGTA Cytosol chemistry Biochemistry L-Glucose B cell ultrastructure Calcium distribution Ciencias Médicas symbols Female Intracellular Subcellular Fractions |
| Zdroj: | SEDICI (UNLP) Universidad Nacional de La Plata instacron:UNLP |
| Popis: | Localization and quantification of calcium pyroantimonate precipitates within the B cells, and determination of insulin secretion were performed in rat pancreas perfused with 3.3 and 16.6 mmol/l glucose. Observations were carried out during the peak, the refractory period, and at 10 and 20 min in the second phase of glucose secretion after the start of a glucose challenge. Specific calcium pyroantimonate precipitates, assessed by EGTA cross-incubation, appeared attached to plasma membrane, Golgi complex, mitochondria, cytoplasmic matrix and secretory granules. The total number of cellular calcium pyroantimonate precipitates increased with perfusion time, being significantly higher at every time-point with the higher concentration of glucose (16.6 mmol/l) than with the 3.3 mmol/l glucose concentration. Calcium pyroantimonate precipitates showed a progressive increment both in plasma membranes and mitochondria. In the cytoplasmic matrix, B granules and Golgi complex, a sharp increase in the number of precipitates was detected at the refractory period, followed by a continuous decrease until the end of the experiment. These results show that the number of calcium pyroantimonate precipitates, localized in different organelles, changes according to the functional state of B cells. They stress the importance of intracellular readily exchangeable pools as regulators of calcium availability for insulin stimulus-secretion coupling. Centro de Endocrinología Experimental y Aplicada |
| Databáze: | OpenAIRE |
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