<qa>  What is the effect of the GLP-1 receptor agonist exenatide on cerebral bloodThis double-blinded, randomized, controlled trial investigates the effect of a single dose of the GLP-1 receptor agonist, exenatide, on cerebral blood flow velocity, cortical oxygation and endothelial function in subjects free of cerebrovascular diseases. To our knowledge, the effect of GLP-1 receptor agonists on cerebral blood flow velocity in healthy subjects has not yet been clarified, and this study serves as a control for a similar study investigating the effect on stroke patients ref. to EGRABIS1. 