Stimulation of pyloric motility by intraduodenal dextrose in normal subjects

Recent studies suggest that the pylorus may play an important role in the regulation of the gastric emptying of nutrient liquids in man. Dextrose solutions in the range 5-25 g/dl have been reported to empty from the human stomach at a constant caloric rate of 2.1 kcal/min. This study examined, in 12 healthy volunteers, the effects of intraduodenal dextrose on pyloric motility. Dextrose solutions, 5, 10, 15, and 25 gde/dl and saline solutions, 0.9 and 2.7 g/dl were infused into the duodenum at 4 ml/min for 10 minutes. Antral, pyloric, and duodenal motility were monitored with sideholes and a sleeve sensor positioned across the pylorus. Significant increases in the rate of isolated pyloric pressure waves and in basal pyloric pressure were seen with 15 and 25 g/dl dextrose (p less than 0.02) and 2.7 g/dl saline (p less than 0.05). The intensity and duration of the phasic and tonic pyloric motor responses to intraduodenal dextrose were dose dependent and correlated directly with the rate of calorie delivery (p less than 0.005 for each parameter). Intraduodenal delivery of dextrose at a rate in excess of 2.1 kcal/min stimulates both phasic and tonic pyloric contraction. These changes in pyloric motility may contribute to the close regulation of the emptying of dextrose from the stomach.