Blood Cell and Plasma Amino Acid Levels Across Forearm Muscle During a Protein Meal

To elucidate the role of blood cells in amino acid metabolism, substrate balance across the forearm was studied in a nitrogen-depleted subject fed 200 gm. of meat. After ingestion of the meal, there was the expected outpouring of amino acids from the splanchnic bed into the general circulation. Both cell and plasma levels of most amino acids in arterial blood increased rapidly. Whole blood arterio-deep venous amino acid differences frequently differed from that of plasma. In conclusion, it appears that both blood cells and plasma transport amino acids from the splanchnic bed to the periphery and that both participate actively in the deposition of amino acids in the forearm of the subject studied.