Influence of jejunal nutrients on transpyloric flow and pyloric resistance in pigs

The effects of small intestinal infusion of nutrients on the transpyloric flow and pyloric resistance were evaluated in anaesthetized pigs. Saline versus isocaloric solutions of dextrose, triglycerides and casein were infused into a jejunal loop during saline gastric loading. Antropyloroduodenal pressures were measured with a sleeve/side-hole manometric assembly and the transpyloric flow with an electromagnetic flowmeter probe. Fundic pressure was maintained constant. Although the overall gastric emptying rate was not affected by nutrients, the stroke volume of the transpyloric flow pulses was significantly increased as a consequence of larger peak flow (dextrose) or longer duration of flow pulses (triglycerides and casein). Pyloric resistance was reduced by all nutrients owing to a change in the temporal relationship between the onset of pyloric pressure events and flow pulses so that flow pulses occurred after pyloric pressure events. In conclusion, under controlled fundic pressure, nutrient infusions decrease pyloric resistance.