Leukocyte amino acid concentrations and their relationship to changes in plasma amino acids

The leukocyte was selected as an accessible example of an actively metabolizing cell. Plasma and leukocyte amino acids (AA) were studied in a reference group and a group of 12 patients receiving total parenteral nutrition. Differences in the plasma AA were variable; some were higher and others lower in concentration in the infused group. Leukocyte AA concentrations were almost all higher in the infused group and the AA pattern was less altered than in plasma. An explanation of the changes is proposed which helps to clarify the relationship of plasma to cellular AA changes.