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Intracellular calcium, insulin secretion, and action
1Medical Research Service, Veterans Administration Medical Center, Denver, Colorado 80220.
The American Journal of Medicine
|November 28, 1988
Summary
Cytosolic calcium (Ca2+) is vital for insulin release and action. Maintaining optimal calcium levels is crucial for pancreatic islet and insulin target cell function, with imbalances potentially causing impaired secretion and action.
Area of Science:
- Cellular Biology
- Endocrinology
- Physiology
Background:
- Cytosolic free calcium concentration ([Ca2+]i) is a key signal transducer.
- Changes in [Ca2+]i involve calcium fluxes or intracellular store mobilization.
- In pancreatic islet cells, elevated [Ca2+]i is critical for insulin release.
Purpose of the Study:
- To investigate the role of cytosolic calcium in insulin secretion and action.
- To explore the mechanisms of glucose-induced calcium changes in pancreatic islets.
- To determine the optimal range of cytosolic calcium for cellular responsiveness.
Main Methods:
- Analysis of cytosolic free calcium concentration changes.
- Investigation of calcium fluxes and intracellular calcium stores.
- Assessment of insulin release and insulin action in response to calcium levels.
Main Results:
- Glucose increases [Ca2+]i in pancreatic islets, primarily via calcium influx.
- Glucose can mobilize intracellular calcium stores, requiring extracellular calcium.
- Optimal cytosolic calcium concentrations (140-350 nM) are essential for pancreatic islet and adipocyte function.
Conclusions:
- Cytosolic calcium plays a complex role in insulin secretion and action.
- Impaired calcium homeostasis may underlie defects in both insulin secretion and action.
- Maintaining cellular calcium balance is crucial for metabolic health.