The two gut-derived hormones, glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1 (GLP-1) are secreted from intestinal cells in relation to a meal and increase insulin secretion from the pancreas. The hormones also exert effects outside the pancreas, but especially for GIP, these are poorly investigated. Because of this, only GLP-1 based drugs (GLP-1 receptor agonists) are on the market for the treatment of type 2 diabetes and obesity. Nonetheless, a new drug is in clinical development: a combined GIP-GLP-1-receptor agonist (tirzepatide), which has shown better results than GLP-1 alone. The mechanism behind these impressive effects are unknown and in this study, the investigators will look into the exptrapancreatic effects of GIP and GLP-1, separate and combined and thus elucidate the mechanisms of action of this new drug class.

Inclusion Criteria:

• Total pancreatectomy
• Caucasians between 30-75 years of age
• Blood haemoglobin >7.0 mmol/l for males and >6.5 mmol/l for females

Exclusion Criteria:

• Pancreatectomy within the last 3 months
• Ongoing chemotherapy or chemotherapy within the last 3 months
• Treatment with GLP-1 receptor agonists within the last 3 months
• Renal impairment (estimated by estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m2) and/or albuminuria
• Calcium related disease, hypo-/hyperthyroidism
• Known significant liver disease, plasma alanine aminotransferase (ALT) or aspartate aminotransferase (AST) ≥3 × normal value or INR (The international normalised ratio based on prothrombin time) outside the normal range
• Severe arteriosclerotic heart disease or heart failure (New York Heart Association (NYHA) group III or IV)
• Pregnancy and/or breastfeeding
• Use of more than 14 units of alcohol per week or abuse of narcotics
• Any condition that the investigator feels would interfere with trial participation