Pancreatic islets were microdissected from ob/ob mice, loaded for 2 h with 45Ca and perifused with calcium-deficient medium. Irrespective of the glucose and calcium concentrations in the loading medium, increased glucose in the perifusion medium resulted in reduced amounts of radioactivity in the perifusate. A glucose inhibition of 45Ca washout was also evident when the specific radioactivity of the islets approached that of the labeling medium, indicating that the effect was not simply due to isotopic dilution. The depression of 45Ca washout diminished after culture of the islets in a serum-free medium and it was absent in islets taken from mice homozygous for the gene diabetes. The glucose effect became less pronounced when 50 μM D-600, an inhibitor of the calcium inward transport, was added to the calcium-deficient perifusion medium and abolished in the presence of 20 mM Ca-EGTA. The inhibition of the 45Ca washout observed is not necessarily due to a direct glucose interaction with the outward calcium transport but may also result from stimulation of the uptake and intracellular trapping of the cation.
|Original language||English (US)|
|Journal||American Journal of Physiology Endocrinology Metabolism and Gastrointestinal Physiology|
|State||Published - Jan 1 1978|
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