Background/Aims: We previously found that somotostatin (SS) inhibited amylase release partly by inhibiting basal cellular cAMP formation in pancreatic acini. In the present study, we verified the effect of SS on intracellular calcium pathway in pancreatic acini isolated from rats, using a synthetic SS analogue, octreotide. For that purpose, permeabilized acini were employed and intracellular calcium concentration ([Ca2+]i) was measured. Methods: Dispersed pancreatic acini were isolated from rat pancreas and amylase release was measured. Pancreatic acini were permeabilized using strep tolysin O (SLO) to maintain a constant optional [Ca2+]i. The [Ca2+]i was determined using fura-2/AM Results: In SLO-permeabilized pancreatic acini, CCK-8 increased amylase release despite high [Ca2+]i. The increased amylase release was significantly inhibited by octreotide. In normal dispersed acini, amylase release stimulated by CCK-8 and carbachol was inhibited by octreotide. CCK-8 and carbachol significantly increased [Ca2+]i. However, Octreotide alone did not have any effect on [Ca2+]i. Increases in the [Ca2+]i induced by CCK-8 and carbachol were augmented by octreotide Conclusions: From the above result, it is concluded that octreotide inhibits CCK-induced amylase release irrespective of intracellular calcium, and increased [Ca2+]i in response to octreotide is no related directly to inhibition of pancreatic amylase release. (Kor J Gastroenterol 1998;32:782 - 791)