Free amino acids in cerebrospinal fluid.

Values for total amino acid nitrogen and for certain individual amino acids in cerebrospinal fluid have been reported in the literature. The values for total a-amino acid nitrogen show some variations, perhaps depending on the methods employed. Weichmann and Dominicke (I), using the Folin calorimetric method, report values of 1.2 to 2.0 mg. per cent, while Christensen et al. (2), using the manometric ninhydrin procedure, report 1.04 to 1.43 mg. per cent of amino nitrogen. Harris (3) has reported the glutamine content of cerebrospinal fluid to be 6.0 to 11.9 mg. per cent. Christensen et al. (2), using chemical methods, report the glycine values for spinal fluid to be about one-tenth and the alanine values to be about one-third of the corresponding values for blood plasma. We are presenting results of the determination by microbiological methods of eleven individual amino acids in spinal fluid.