Gastric and duodenal features of meals mediate controls of liquid gastric emptying during fill in rhesus monkeys

To study the dynamics of liquid gastric emptying in rhesus monkeys under conditions that simulated gastric fill during a meal, we measured the gastric emptying of liquid glucose at various concentrations and volumes when administered intragastrically at rates ranging from 12.5 to 37.5 ml/min. Glucose gastric emptying was faster during than following the period of gastric fill. At a single glucose concentration, volume infused rather than the rate of filling determined the volume emptied. Lower glucose concentrations emptied more slowly than physiological saline. As glucose concentration increased, emptying during fill slowed. Duodenal glucose infusions greatly slowed the rate of saline emptying during fill, demonstrating duodenal feedback control. Although casein hydrolosate emptied more rapidly than glucose, the dynamics of volume and concentration dependency and the role of duodenal feedback were similar. These data reveal that both gastric volume and duodenal negative feedback controls important in gastric emptying following stomach filling also contribute to its control during fill.