GLP1R and type 2 diabetes mellitus: Such a direct GLP-1 mechanism is supported by studies using native GLP-1 and exenatide in healthy people and patients with T2DM showing that the acute increase of HR was not preceded by a decrease in blood pressure, was not associated with changes in plasma levels of adrenaline or noradrenaline, and was independent of GLP-1 glucoregulatory effects [11, 34, 35].