Free Amino Acids in Serum, Cerebrospinal Fluid, and Urine in Renal Disease With and Without Uremia

Summary Free α-amino-nitrogen and free amino acids have been measured in the serum, urine, and cerebrospinal fluid (c.s.f.) of 51 patients with severe uremia and 20 patients with renal disease without uremia. The results have been compared with those obtained from a study of 50 patients without renal disease. Severe uremia was found to be associated with a highly significant increase in the levels of almost all amino acids in the cerebrospinal fluid. In particular aromatic amino acids and glutamine are elevated. This increase probably reflects increased blood levels of free amino acids and an increase in the permeability of the blood-brain barrier in uremia.