 We intend to study the effect of oral administered BCAA on the metabolism of ammonia and amino acids across the leg-muscles by means of catheters inserted into the femoral artery A and vein V. Muscle blood flow F; Lmin will be determined by constant infusion of indocyanine green and indicator dilution principle. Arterial blood flow and A and V concentrations of ammonia and amino acids will be measured before an oral load of BCAA 0.45 g BCAAkg body weight and after 1 and 3 hours. The metabolism of ammonia will also be estimated by means of 13N-NH3 PET scans. 