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 effe ct of basic fibroblast growth factor (bFGF) on both amylase secretion and intracellular free calcium concentration ([Ca2+](i)) in response t o the calcium-mobilizing secretagogue cholecystokinin-octapeptide (CCK -8). Our data show that bFGF inhibited CCK-8-induced amylase release i n a concentration-dependent manner and decreased the CCK-8-induced ris e in [Ca2+](i). This inhibitory effect of bFGF on both amylase secreti on and [Ca2+](i) increase in response to CCK-8 was reverted when acina r cells were pretreated with 100 mu M tyrphostin A25, a tyrosine kinas e inhibitor. Tyrphostin A25 also inhibited Ca2+ influx induced by CCK- 8. These results show that bFGF inhibits CCK-8-induced pancreatic resp onse by a tyrosine kinase-dependent mechanism. A role for tyrosine pho sphorylation in capacitative Ca2+ entry is suggested. (C) 1998 Elsevie r Science Inc.