The Effect of GIP, GLP-1 and GLP-2 in Individuals With Genetically Altered Receptor Function (H-21044858)

Participants with mutations in their GLP-1- and GIP receptor will attend five randomized experimental days, A1, A2, B, C and D. On day A1 an oral glucose tolerance test (OGTT) will be performed, and on day A2, an intravenous isoglycaemic glucose infusion (IIGI) will be performed. On experimental day B and C, the study participants will receive GLP-1 and GIP hormones, respectively, under stable glucose infusions and on experimental day D, they will receive infusion of salt water (placebo) under stable glucose infusion. Participants with mutations in their GLP-2 receptor will attend three randomized experimental days, E, F and G. A mixed meal test (MMT) will be performed on day E, an infusion with GLP-2 during fasting blood glucose levels will be performed on day F, and infusion with salt water (placebo) during fasting blood glucose levels will be performed on day G. Additionally, a DXA scan and arginine test will be performed on all study participants.