Does glucose decrease cytosolic free calcium in normal pancreatic islet cells?

Cytosolic free Ca2+ concentration ([Ca2+]i) was measured in normal rat pancreatic islet cells using the intracellular Ca2+ indicator fura 2. Glucose induced an initial decrease followed by a secondary rise in [Ca2+]i. The secondary rise probably resulted from an increase in Ca2+ inflow into the cells, while the initial decrease displayed several characteristics of the well known initial decrease in 45Ca efflux induced by glucose in prelabelled pancreatic islets. It is concluded that glucose may exert both an inhibitory and a stimulatory effect on [Ca2+]i in normal isolated islet cells.