12 healthy male subjects aged 18-45 years with BMI 20-27 kg/m2 will be recruited. Subjects will attend for an initial screening visit and initial assessments. This will enable familiarization with the room and equipment to be used. On arrival at the laboratory, subjects will be asked to void their bladder and a urine collection will be commenced. Subjects will be asked to wear shorts during the study and rest semi-supine on a hospital bed. They will place their hand in a heated hand warming unit and an intravenous cannula will be inserted, for arterialized venous blood sampling,. Subjects will rest for 1hour before receiving either Exenatide or placebo injection. Measurements of Limb blood flow (by venous occlusion plethysmography); skin blood flow (by laser Doppler); blood pressure, heart rate (HR) and cardiac output (by Finometry™);and regional blood flow (by ultrasound imaging and flow velocity measurement of the superior mesenteric arteries (SMA) will take place every 30minutes. Blood sampling for insulin and glucose will be carried out every 15minutes throughout the study. Subjects will rest for 120 minutes after injection with measurements every 30 minutes as before with blood sampling every 15 minutes until 120 minutes post injection. Subjects will receive a high carbohydrate breakfast 60 minutes post injection. Urine will be collected during the study to assess urinary sodium excretion.