Exenatide is a new drug which lowers blood sugar (glucose) levels for people with type 2 diabetes. It has significant advantages over other treatments such as insulin as it causes weight loss in a group of people that is generally overweight. Data from studies involving exenatide have shown that it also has an effect on blood pressure. The mechanism for the blood pressure lowering effect is not known and has not been investigated previously. Exenatide may have an effect on blood vessels throughout the body and gut to reduce blood pressure. 12 healthy men (18-45yr) will be studied on 2 occasions. Limb blood flow, skin blood flow, gut blood flow, blood pressure, and heart rate will be measured half hourly for 4 hours. Blood samples (3ml) for insulin and glucose determination will be taken via a cannula and 3-way tap at the same time points. A dose of either 5μg exenatide or saline will be injected under the skin of the abdomen and a breakfast will be provided during the study. A urine collection will be made over the duration of the study.