ERYTHROCYTES PARTICIPATE SIGNIFICANTLY IN BLOOD TRANSPORT OF AMINO-ACIDS DURING THE POST ABSORPTIVE STATE IN NORMAL HUMANS

To investigate the participation of erythrocytes in the blood transpor t of amino acids during the course of intestinal absorption in humans, erythrocyte and plasma amino-acid concentrations were determined foll owing ingestion of an oral load of amino acids. In addition to baselin e plasma and erythrocyte amino acid concentrations in 18 subjects, pla sma and erythrocyte amino acids kinetics during the 125 min following an oral amino acid load were further determined in 9 of the 18 subject s. The results showed that human erythrocytes contained most amino aci ds at similar or higher concentrations than plasma. Furthermore, the c orrelations observed between plasma and erythrocyte contents clearly i ndicated that erythrocytes were involved in the transport of amino aci ds by the blood. For some amino acids erythrocyte transport sometimes exceeded that of plasma. Significant correlation coefficients showed t hat strong plasma-erythrocyte relationships existed for alanine, valin e, methionine, isoleucine, leucine, phenylalanine, and ornithine. In c onclusion, our data supported the hypothesis that both blood compartme nts, plasma and erythrocytes, are involved significantly in the blood transport of amino acids in humans during the postabsorptive state.