Effect of acetylcholine, gastrin, and glucagon alone and in combination with secretin and cholecystokinin on the secretion of the isolated perfused rat pancreas

Dose-response curves of acetylcholine (ACh), gastrin, and glucagon given alone or in combination with a submaximal dose of secretin (S; 5.0 U/h) plus cholecystokinin (CCK; 1.0 U/h) were studied in the isolated perfused rat pancreas. ACh (25 × 10⁻⁹ mol/h) increased the basal secretory flow ( $\bar x$ ±SEM: 1.19±0.22 µl/min) by 693% and protein output (2.7±0.2 µg/min) by 1726%. The protein secretion evoked by S plus CCK was further increased by ACh to a maximum of 26% whereas the volume secretion remained unaltered. Gastrin (100 ng/h) stimulated the protein output by 352% and, when combined with S and CCK, up to further 23% and the secretory flow by 37%. Glucagon evoked a significant (P < 0.005) increase of the protein output, but decreased the volume as well as the protein output (by 43% and 32%, respectively;P < 0.05) when it was combined with the tested doses of S and CCK.