Gut sweet taste receptors and their role in metabolism

Obesity is caused by an imbalance between food intake and energy expenditure. In recent decades the gastrointestinal tract has received growing attention as a control parameter for the regulation of appetite and food intake, however regulatory circuits and their interactions are complex. The basic understanding on the role of the gut starts with the notion 'we are what we eat'. Food enters the gastrointestinal tract, which then triggers specific mechanisms or a sensing machinery that respond to specific components of food. Enteroendocrine cells in the small intestine are the anatomical basis for the sensing machinery, which act as neural triggers or as intestinal satiation peptide-secreting cells. These cells express chemosensory receptors that respond to luminal stimuli. The understanding of each gastrointestinal mechanism that might be involved in the process of eating provides a basis for the assessment of the potential of the gastrointestinal tract in the fight against obesity. This review discusses the function of the gut sweet taste receptor T1R2/T1R3 in sensing sweet compounds, as well as its role in gastrointestinal peptide secretion and glucose metabolism.