[Protein and amino acid metabolism in chronic renal failure]

Some degrees of protein deficiency, suggestive of abnormal protein metabolism, are a well-known feature of chronic renal failure (CRF). Serum albumin concentration, an index of malnutrition and deranged protein metabolism, is frequently decreased relatively early in CRF, even in absence of heavy proteinuria: a more subtle but characteristic abnormality is found in the plasma profile of amino acids. In addition, there is an accumulation in the plasma and tissues of many products of protein metabolism; some of these have been considered as uremic toxins, while others are largely undefined. The origin of abnormalities in protein metabolism are multifactorial. The defect are caused at least partly by dietary deficiency, as well as by the inability of the failing kidney to excrete normal end products of nitrogen and protein metabolism and by the effect of altered uremic milieu on overall metabolism.