[Free amino acids in the brain of vertebrates].

Studies have been made on the content of free amino acids in the brain of the pike Esox lucius, frog Rana ridibunda, pheasant Phasinus colhidus, hare Lepus europaeus, as well as their distribution in the white and grey matter of healthy human subjects. Differences in the distribution of free amino acid pool were found between man and animals. In the grey matter of human brain, large quantities of free ornithine, phenylalanine, lysine, serine, glycine, alanine, tyrosine, tryptophan, methionine, leucine and isoleucine, as well as lower level of aspartic acid, glutamic acid and threonine were found as compared to the white matter. The content of ornithine, serine and threonine increases in the row birds greater than fishes greater than man greater than mammals greater than amphibians; histidine and arginine pool increases in the following sequence: birds greater than fishes greater than mammals greater than amphibians greater than man.