Use of digitonin permeabilization for characterization of calcium incorporated into beta-cells in response to glucose.
beta-Cell rich pancreatic islets were used to characterize 45Ca uptake into pools with different sensitivities to permeabilization with digitonin. The plasma and secretory granule membranes were among the membranes most sensitive to digitonin treatment whereas the mitochondria were more resistant. Most of the 45Ca incorporated in response to glucose was found in a fraction released after exposure to a high concentration of digitonin. The results suggest that glucose promotes active sequestration of calcium in mitochondria and that the uptake of 45Ca in the secretory granules is secondary to a raised cytosolic Ca2+ activity.
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002463:Cell Membrane Permeability; D002784:Cholesterol / Q000378:metabolism; D004072:Digitonin; D005947:Glucose / Q000494:pharmacology*; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism*; D008563:Membrane Lipids / Q000378:metabolism; D051379:Mice; D008820:Mice, Obese
D008563:Membrane Lipids; D002784:Cholesterol; D005947:Glucose; D004072:Digitonin; D002118:Calcium