The effect of native GLP-1 on glucose uptake in the brain and heart will by visualized by fluoro-deoxy-glucose FDG-PET-scan during normoglycaemia in healthy young men. At the same time a pancreatic/pituitary clamp will be performed. The hypothesis is that GLP-1 directly will stimulate glucose uptake independent of the pancreatic hormones and through this mechanism exert its neuro- and cardioprotective actions.