Introduction: Protein loss during critical illness is an important problem and is shown to predict overall survival. In animal studies, infusion of leucine is shown to increase the synthesis of muscle protein by 30-40% and decrease protein degradation by 30%.

Objectives: Compared to saline, an amino acid or 3hydroxybutyrate infusion in the femoral artery will promote protein synthesis and inhibit breakdown assessed with local a/v phenylalanine and tyrosine tracer kinetics in healthy volunteers. These effects will include distinct alterations in muscle signal events, in particular mTOR.

Methods: n = 10 healthy male subjects are equipped with catheters in aa. femorals and vv. femorals bilaterally under local anaesthetics. Each study comprises a 3-hour basal period and a 3-hour period with hyperinsulinaemic-euglycaemic clamp. During the test, samples of arterial and venous blood and 4 muscle biopsies are obtained. The intervention contain continues saline infusion compared to either amino acids (Vamin) or 3hydroxybutyrate solution FFa-3OHB.

Perspectives: This study elucidates the direct effect of aminoacids and ketone bodies on muscle protein metabolism in humans and contribute to further development of nutritional therapy in human catabolic states.

Inclusion Criteria:

• BMI between 19 and 28
• Written consent before study start

Exclusion Criteria:

• Diabetes
• Inclusion in other studies using ionizing radiation.
• Allergic to egg or soy