Effect of Basic Fibroblast Growth Factor on Cholecystokinin-Induced Amylase Release and Intracellular Calcium Increase in Male Rat Pancreatic Acinar Cells

Isolated rat pancreatic acinar cells were used to investigate the effect of basic fibroblast growth factor (bFGF) on both amylase secretion and intracellular free calcium concentration ([Ca 2+] i) in response to the calcium-mobilizing secretagogue cholecystokinin-octapeptide (CCK-8). Our data show that bFGF inhibited CCK-8-induced amylase release in a concentration-dependent manner and decreased the CCK-8-induced rise in [Ca 2+] i. This inhibitory effect of bFGF on both amylase secretion and [Ca 2+] i increase in response to CCK-8 was reverted when acinar cells were pretreated with 100 μM tyrphostin A25, a tyrosine kinase inhibitor. Tyrphostin A25 also inhibited Ca 2+ influx induced by CCK-8. These results show that bFGF inhibits CCK-8-induced pancreatic response by a tyrosine kinase-dependent mechanism. A role for tyrosine phosphorylation in capacitative Ca 2+ entry is suggested.