The purpose of this study is to determine the functional significance of sweet taste receptors in the secretion of GI satiation peptides by using a specific sweet taste receptor antagonist to block sweet taste perception in the gastrointestinal tract.

There is strong evidence that taste signaling mechanisms identified in the oral epithelium also operate in the gut. It is suggested that open-type enteroendocrine cells directly sense nutrient via alpha-gustducin coupled taste receptors to modulate the secretion of glucagon like peptide-1 (GLP-1) and peptide YY (PYY). Several nutrient responsive G-protein coupled receptors have been identified in the human gut, including the sweet taste responsive T1R2/T1R3 heterodimer, the amino acid/umami responsive T1R1/T1R3 as well as GPR120 for unsaturated long-chain free fatty acids.The functional significance of sweet taste receptors in the secretion of GLP-1 and PYY will be determined by intraduodenal perfusion of glucose (I) or a mixed liquid meal (II) with or without lactisole (450 ppm) in a double blind, 5-way crossover trial including 10 healthy subjects.

Inclusion Criteria:

• Healthy subjects
• BMI of 19.0-24.5
• Age 18-40
• stable body weight for at least 3 month

Exclusion Criteria:

• smoking
• substance abuse
• regular intake of medication
• medical or psychiatric illness
• gastrointestinal disorders or food allergies