Plasma amino acid patterns in normal Thais and in patients with chronic renal failure.

The effect of chronic renal failure (CRF) on the pattern of plasma free amino acid concentrations was studied in 22 healthy controls (group 1); 43 CRF patients of which serum creatinine levels were 2-4.9 mg/dl (group 2, n = 11), 5-10 mg/dl (group 3, n = 10), more than 10 mg/dl (group 4, n = 9), and chronically hemodialysed patients (group 5, n = 13). In all renal failure groups, plasma concentrations of eight free essential amino acids-isoleucine, leucine, lysine, methionine, threonine, tryptophan, tyrosine and valine and those of three non-essential amino acids-alanine, glutamate and serine were significantly lower than those in controls. Plasma concentrations of free arginine, cystine, glutamate and serine were significantly higher in CRF patients. Patterns of change of plasma aminogram were similar among CRF patients regardless of the stages of renal function or dialytic treatment. Stepwise changes of some plasma free amino acids were observed as renal function became worse. The molar ratios of plasma free valine/glycine, serine/glycine and tyrosine/phenylalanine were decreased accordingly. Our study confirms the presence of abnormal plasma aminogram, specifically that of essential amino acids, in CRF. Therapeutic intervention is warranted but still needs further investigations.