Catabolic stress on intracellular amino acid pool.

Abstract

Many studies have documented abnormal plasma concentrations of the free amino acids in patients with different catabolic disorders. The interpretation and the pathogenesis of these abnormal patterns, however, remain speculative. Certain abnormalities appear to be caused by the catabolic stress per se, whereas others, resembling those observed in subjects with low intake of protein and energy, may be related to malnutrition. During catabolic stress the distribution of free amino acids showed to be altered between the extracellular and intracellular compartments1–6. Therefore the plasma concentrations do not necessarily reflect the intracellular concentration. Since skeletal muscle contains the largest pool of free amino acids, determination of the free amino acid concentration in muscle might be of particular interest in the study of amino acid and protein metabolism during catabolic stress and subsequent repletion.