Total-body Glucose Utilization in Obesity

Participants will watch eight short movie clips, and the changes different emotions evoked by the clips will be studied using H2\[15O\]O PET/CT.

Participants will be studied with H2\[15O\]O PET/CT while one of their legs will be exposed to cold to study the effects of cold stimulus on whole-body blood flow.

Participants will be administered intravenous fast acting insulin (NovoRapid, Novo Nordisk, 1 mU/m2 body surface area/min) together with 20 % glucose to maintain normal glucose values (5.0 mmol/L) to study the effects of insulin on whole body blood flow with H2\[15O\]O PET/CT, and to assess tissue insulin-stimulated glucose uptake with \[18F\]FDG PET/CT.

H2\[15O\]O PET/CT, with a dose of 25-700 MB/bolus repeated 2-8 times per scan.

Whole-body \[18F\]FDG PET/CT scan to study tissue glucose uptake, dose 100 MBq

Contrast-enhanced ultrasound of left forearm muscles is performed during fasting and after 30-40 minutes of hyperinsulinemia