[Intracellular amino acid concentrations in various disease states]

The determination of free amino acids (AA) in human tissue is far more complicated than the analysis of plasma AA. The concentrations of free AA are different in plasma, liver and muscle, respectively. Pathological conditions like sepsis, liver failure and glucagonoma syndrome lead to characteristic alterations in the concentrations of free AA. However, the relationship between cytosolic AA concentrations and protein synthesis are not yet clear. Possibly drastically reduced levels of single AA (e.g. glutamine) lead to a 'down'-regulation of protein synthesis.