The physiology of gastric emptying

The gastric emptying rate is a carefully regulated process consisting of different mathematically defined phases. The gastric metabolic load, as well as neural regulatory mechanisms and hormonal influences, cooperate in order to achieve a well-balanced emptying of contents from the stomach into the duodenum for absorption in the small intestine. This finely tuned regulation is primarily regulated by the release of gastrointestinal peptide hormones which serve to counteract the emptying process in the fed state and to stimulate sweeping contractions in the fasted state, most likely in order to prepare the stomach for another meal. We have found that the two peptide hormones ghrelin and glucagon-like peptide-1 (GLP-1) have a great impact on the regulation of gastric emptying: ghrelin is a most potent stimulator of gastric contractions and emptying, and GLP-1 profoundly inhibits this emptying process. These data suggest possibilities for governing the rate of gastric emptying as a natural step in achieving metabolic balance and control.

Key words: stomach, scintigraphy, metabolism, gut hormones, ghrelin, GLP-1