EFFECTS OF THE GUT HORMONES ON GASTRIC-EMPTYING

The term gastric emptying is applied for the process by which gastric contents enter the duodenum, Physiologically, the stomach is usually divided into orad stomach, and caudad stomach. There are differences between the two in the electric activity and motor functions. The gastric emptying is regulated by neurohumoral factors, especially gut hormones. The present address discusses several main gut hormones involved in regulation of gastric motility and emptying. CCK/gastrin family contains mainly CCK and gastrin, and, both hormones inhibit gastric emptying of liquid and/or solid food by binding to their receptors, or through nerve reflex. PP-fold family of peptide contains PTY, NPY, and PP. PYY, NPY inhibit gastric emptying by suppressing contraction of smooth muscle. In contrast, PP stimulates smooth muscle of gastrointestinal tract to accelerate gastric emptying. Secretin/glucagon family contains VIP, glucagon, secretin, etc. VIP may act as an inhibitory neurotransmitter of the non-adrenergic, non-cholinergic nerve system, and can inhibit gastric emptying. The action of VIP seems to be mediated through an interaction with the adenylate cyclase system leading to a mobilization of intracellular cAMP. Glucagon can diminish gastric emptying by vagal mechanism. Secretin can inhibit human fundic and antral contraction, and then delay gastric emptying of liquid. In addition, galanin, somatostatin, motilin, and so on can influence gastric emptying.