METABOLIC-ACIDOSIS AND PROTEIN CATABOLISM - MECHANISMS AND CLINICAL IMPLICATIONS

Metabolic acidosis increases protein degradation resulting in muscle w asting and a negative nitrogen balance. The branched-chain amino acids serve as useful markers of these changes and their catabolism is incr eased in acidosis, particularly for the spontaneous acidosis associate d with renal failure. As a result, the neutral nitrogen balance is com promised and malnutrition results. Glucocorticoids mediate these chang es through the recently discovered ATP-dependent ubiquitin-proteasome pathway. Therapy necessitates correction of the underlying acidosis ei ther through adjustment of the alkalinity of the dialysate for the pat ient on dialysis or through dietary protein restriction and sodium bic arbonate supplements for the predialysis patient.