Pancreastatin increases cytosolic Ca2+ in insulin secreting RINm5F cells.

We have investigated the effect of pancreastatin on cytosolic Ca2+ concentration in the insulin secreting cell line RINm5F. Changes in [Ca2+]i induced by pancreastatin were detected by Fluo-3 fluorescence using both flow cytometry and batch analysis measurements, and turned out to be from 90 to 315 nM equivalent to 80% of that caused by ATP, which increased [Ca2+]i from 90 nM to 400 nM. This effect of pancreastatin did not depend on extracellular calcium and was not mediated by alpha-adrenergic receptors since it was not prevented by the alpha-blocker yohimbine. It is concluded that pancreastatin has a role in the homeostasis of free cytosolic calcium in the insulin secreting cell line Rinm5F.