Somatostatin secretion from the isolated perfused dog ileum

The present study was designed to examine ileal D cell function. The influence of perfusate calcium, potassium, arginine, and glucose on release of somatostatin (SS) was measured using an isolated, perfused dog ileum preparation. Ileal SS release was significantly enhanced by an increase in extracellular calcium from 0-1.3 mM (from 11 +/- 3 pg/ml to 37 +/- 11 pg/ml; 2 P less than 0.05). In the presence of a normal calcium level (1.3 mM) an increase in potassium from 4.4-13.8 mM caused enhanced SS output (from 46 +/- 8 pg/ml to 74 +/- 10 pg/ml; 2 P less than 0.05). The addition of arginine (10 mM) elicited a prominent rise in SS secretion (from 105 +/- 8 pg/ml to 184 +/- 30 pg/ml; 2 P less than 0.05) while enhancement in glucose from 5-20 mM was without effect (57 +/- 13 pg/ml vs. 57 +/- 14 pg/ml). Thus it appears that ileal D cells release SS in response to changes in certain appropriate stimuli, but in contrast to those D cells situated in other parts of the gastrointestinal tract, e.g. the pancreas, they are apparently nonresponsive to glucose.