Ribosome and free amino acid content in muscle during hemodialysis.

Patients (N = 8) with chronic renal failure and uremia treated with hospital hemodialysis were in a pilot study investigated before and after a single hemodialysis session. The extracorporeal dialysis circuit was flushed regularly with saline to avoid clotting and the use of heparin. Percutaneous skeletal muscle biopsies were taken before and after the dialysis to determine the content of free amino acids together with the concentration and size distribution of ribosomes before and after dialysis. After dialysis the alanine concentration in muscle decreased by 20% (P less than 0.05), while all other amino acids were unaffected. The total ribosome concentration per mg of DNA decreased by 31% (P less than 0.01) and the relative proportion of polyribosomes by 7% (P less than 0.05) after the dialysis compared to predialytic values. All individual plasma amino acids decreased during the dialysis procedure except for threonine and arginine, which were unaltered, and leucine and isoleucine, which increased. The decline in ribosome and polyribosome content together with the changes in amino acid levels indicate a low capacity for protein synthesis and increased catabolism in muscle of hemodialyzed patients.