This study was undertaken to examine the role of K+ channels on cytosolic Ca2+ ([Ca2+] i)
in insulin secreting cells.[Ca2+] i was measured in single glucose-responsive INS-1 cells
using the fluorescent Ca2+ indicator Fura-2. Glucose, tolbutamide and forskolin elevated
[Ca2+] i and induced [Ca2+] oscillations. Whereas the glucose effect was delayed and
observed in 60% and 93% of the cells, in a poorly and a highly glucose-responsive INS-1
cell clone, respectively, tolbutamide and forskolin increased [Ca2+] i in all cells tested. In the …