THE EFFECT OF SOMATOSTATIN ANALOG OCTREOTIDE ON AMYLASE SECRETION FROM MOUSE PANCREATIC ACINI

To clarify whether somatostatin has an inhibitory effect on pancreatic acinar cells, we studied the effect of a long-acting analogue of somatostatin, octreotide, on amylase secretion from isolated mouse pancreatic acini. Octreotide (100 nM) had no inhibitory effects on amylase secretion stimulated by secretin or vasoactive intestinal polypeptide (VIP), while reducing the increase of cyclic adenosine 3',5'-monophosphate (cAMP). On the other hand, octreotide inhibited synergistic amylase secretion induced by secretin or VIP in combination with cholecystokinin (CCK). Octreotide also reduced synergistic amylase secretion by secretin or VIP in combination with calcium ionophore A23187. CCK and A23187 did not alter the increase of cAMP induced by secretin and the inhibitory effect of octreotide on cAMP production. Octreotide did not significantly inhibit amylase secretion stimulated by dibutyryl cAMP (dbcAMP) alone, but reduced synergistic amylase secretion by dbcAMP+A23187. Results obtained above reveal that octreotide has a direct inhibitory effect on amylase secretion from mouse pancreatic acini and probably affects stimulus secretion coupling at a point distal to the production of cAMP, besides inhibiting adenylate cyclase.