Dynamics of gastric emptying during and after stomach fill

Gastric contents were sampled at various points during and after intragastric infusions of glucose solution (6.25, 12.5, 25%) delivered at rates typical of normal ingestion in the rat. The postinfusion results were consistent with those reported in the literature in that glucose solute emptied at a relatively stable rate over time and across stimulus concentrations. During fill (1.0 ml/min; experiment 1), by contrast, solute (caloric) emptying rate increased about threefold as stimulus concentration was raised. For each concentration, emptying rate was uniformly higher during than after fill (approximately 4 times higher at the lowest concentration). In experiment 2, gastric emptying rate during 12-min intragastric infusions of 12.5% glucose varied directly with the volumetric rate (0.5, 1.0, 2.0 ml/min) at which they were delivered. These results show that different rules govern gastric emptying during and after stomach fill. The results also suggest that a large proportion of a liquid meal may empty before feeding is terminated and that variations in the rate of ingestion could affect the gastric/postgastric distribution of ingesta and, in turn, the satiation process.