Relationship between oral glucose tolerance and gastric emptying in normal healthy subjects

Summary The relationships between gastric emptying and intragastric distribution of glucose and oral glucose tolerance were evaluated in 16 healthy volunteers. While sitting in front of a gamma camera the subjects drank 350 ml water containing 75 g glucose and 20 MBq ^99mTc-sulphur colloid. Venous blood samples for measurement of plasma glucose, insulin and gastric inhibitory polypeptide were obtained at — 2, 2, 5, 10, 15, 30, 45, 60, 75, 90, 105, 120 and 150 min. Gastric emptying approximated a linear pattern after a short lag phase (3.3±0.8 min). The 50% emptying time was inversely related to the proximal stomach 50% emptying time (r=–0.55, p<0.05) and directly related to the retention in the distal stomach at 120 min (r=0.72, p<0.01). Peak plasma glucose was related to the amount emptied at 5 min (r=0.58, p<0.05) and the area under the blood glucose curve between 0 and 30 min was related to the amount emptied at 30 min (r=0.58, p<0.05). In contrast, plasma glucose at 120 min was inversely related to gastric emptying (r=–0.56, p<0.05) and plasma insulin at 30 min (r=–0.53, p<0.05). Plasma insulin at 120 min was inversely related (r=–0.65, p<0.01) to gastric emptying. The increase in plasma gastric inhibitory polypeptide at 5 min was related directly to gastric emptying (r=0.53, p<0.05). These results indicate in normal subjects that (i) gastric emptying accounts for about 34 % of the variance in peak plasma glucose after a 75-g oral glucose load (ii) plasma glucose levels at 120 min are inversely, rather than directly, related to gastric emptying (iii) the distal stomach influences gastric emptying of glucose.