Enhanced muscle protein catabolism in uremia.

Abstract

Acute and chronic uremia are associated with variable degrees of myopathy, a retardation in growth, and a reduction in lean body mass (1–3). With time, both the upper and lower extremities may demonstrate diffuse muscle atrophy and weakness (3). These data suggest that muscle protein catabolism may be increased, synthesis decreased, or both may coexist in uremia. Significant changes in plasma amino acids occur in both acute and chronic uremia. The plasma phenylalanine to tyrosine ratio is reduced and plasma non-essential amino acid levels are usually normal while the levels of essential amino acids including leucine, isoleucine, valine, and lysine are decreased (4, 5). These data suggest that significant abnormalities in protein metabolism do exist in uremia. Uremic rats fed identical diets exhibit significantly reduced growth rates compared to pair-fed control animals (6). Despite increased protein intake, growth was still impaired in the uremic animals. Thus, these data demonstrate that protein efficiency is reduced in the growing uremic animal. The mechanisms responsible for these observations have not been definitively elucidated.KeywordsExercise TrainingPlasma Amino AcidDietary Protein IntakeAmino Acid ReleaseAdenylate Cyclase SystemThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.