| Theme |
The Roles of Gut Physiological Active Peptides in the Control of Nutrition and Metabolism |
| Title |
Effect of Amino Acids on Incretin Secretion |
| Author |
Hiroko Hosaka |
Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine |
| Author |
Motoyasu Kusano |
Department of Endoscopy and Endoscopic Surgery, Gunma University Hospital |
| Author |
Akiyo Kawada |
Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine |
| Author |
Shiko Kuribayashi |
Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine |
| Author |
Yasuyuki Shimoyama |
Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine |
| Author |
Osamu Kawamura |
Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine |
| [ Summary ] |
After ingestion of a meal, a large variety of physiological reactions occur outside and within the gastrointestinal tract. Recently, the field of nutrient sensing in the gastrointestinal tract has evolved rapidly examining the deorphanization of previously unliganded G-protein-coupled receptors, which respond to important nutrients. One mechanism for the detection of nutrients is linked to nutrient absorption and processing by enterocytes. Another mechanism relates to the occurrence of nutrient-specific receptors on enterocyte luminal cell membranes. Unlike carbohydrates and fats, protein degradation in the digestive process generates a complex mixture of breakdown products, ranging from large oligopeptides to a mixture of individual amino acids. Single L-amino acids, including L-glutamate, increase GLP-1 release from cultured enteroendocrine-like GLUTag cells. We investigated the effects of monosodium L-glutamate (MSG) on glucose homeostasis, incretin secretion and gastric emptying in humans after a liquid meal. MSG stimulated GLP-1 secretion and improved early postprandial glycemia. This effect was not associated with a change in gastric emptying, but is possibly related to stimulation of GLP-1 secretion. |