Clinical Research Directory

Inclusion Criteria: 1. Patients scheduled for GBP surgery or VLCD intervention for obesity as well as patients scheduled for cholecystectomy. 2. BMI ≥ 18.5 kg/m2 3. Able and willing to donate biopsies (as specified in the protocol) and for the GBP and VLCD patients also willing to perform follow-up 24 hour PK-investigations and other assessments as required by the clinical study protocol 4. Stable body weight (\< 5 kg self reported weight change) during the last 3 months before inclusion. 5. Signed informed consent. Exclusion Criteria: * Concomitant treatment with drugs (according to available literature, appendix 3) and/or other factors that may influence the cocktail drug pharmacokinetics such as grapefruit juice, Seville oranges, Pomelo juice, St. Johns wort, tobacco and coffee/tea in close approximation to the investigations. * Bradyarrhythmia, Wolff-Parkinson-White (WPW)-syndrome, atrioventricular block 2-3. * Electrolyte disturbances (particularly hypokalemia or hypomagnesemia). * Renal impairment: eGFR \< 30 mL/min. * Blood donations the last 4 months. * Previous bariatric or upper gastrointestinal surgery. * Diabetic patients treated with glitazones, insulin or sulfonylureas. * Pregnancy (checked with HCG in urine at screening) and breast-feeding mothers. * Known hypersensitivity (including allergy) to drugs included in the cocktail and/or local anesthesia. * Anticoagulants with associated risk in combination with biopsies. * Non-compliance with regards to visits and/or diet.