Studies of cerebrospinal fluid and plasma amino acids in patients with steady-state chronic renal failure.

The concentration of free amino acids in the plasma and lumbar CSF of 11 patients with steady-state chronic renal failure has been measured and the CSF: plasma concentration ratios calculated. The results have been compared with the corresponding data from 37 control subjects. In renal failure, elevation of the mean plasma concentration of total amino acids and a reduction in the ratio of essential to total amino acids have been found. Whereas some individual plasma amino acid concentrations in renal failure were higher than normal, others were lower. Striking abnormalities of the CSF amino acid concentration have been observed. Some amino acids have shown similar patterns of abnormality in both CSF and plasma, whereas in the case of others, the changes have been restricted to either CSF or plasma. Significant variations from normal of the CSF: plasma concentration ratios were observed for four amino acids.