EFFECTS OF GLP-1 ON GASTRIC-EMPTYING, ANTROPYLORIC MOTILITY, AND TRANSPYLORIC FLOW IN RESPONSE TO A NONNUTRIENT LIQUID

Glucagon-like polypeptide 1 (GLP-1) may be a major enterogastrone, slo wing gastric emptying when released by intestinal nutrients. In six co nscious dogs, we studied the effects of GLP-1, on antropyloric motilit y, gastric emptying, and transpyloric flow after instillation of 500 m l of saline into the stomach. The meal was given and recordings were s tarted 15 min after intravenous bolus and infusion of either saline or three different doses of GLP-1. Intravenous GLP-1 produced a dose-rel ated retardation of gastric emptying associated with a decrease in the number and volume of flow pulses in comparison to saline. This change in transpyloric flow was associated with an inhibition of antropylori c pressure waves, a stimulation of isolated pyloric pressure waves, an d an increase in basal pyloric tone induced by intravenous GLP-1 infus ion. Our findings show that GLP-1 has a potent dose-dependent inhibito ry effect on transpyloric flow and gastric emptying. This effect is te mporally associated with inhibition of antral ''pumping'' and stimulat ion of pyloric ''braking'' mechanisms.