Free amino acids and related substances in human glial tumours and in fetal brain: comparison with normal adult brain.

An ion exchange automatic chromatographic analysis of the free amino acid concentrations of 18 human glial tumours and of 4 human fetal brains was carried out and the concentrations were compared to those of 13 biopsy specimens of normal adult brain. In addition, the concentrations of the amino acids of the glial tumours were compared to those of 7 intracerebral metastases of various origin. The chromatograms of several tumour specimens showed an unidentified peak overlapping proline. As far as the amino acid concentrations are concerned they varied depending upon the origin of the sample. The concentrations of most amino acids were higher in fetal brain than in adult brain with the exception of aspartic acid, glutamic acid, glutamine, cystathionine and GABA. Two peptides: glutathione and homocarnosine were absent in fetal brain and were present in adult brain. In glial tumours, homocarnosine and some amino acids, namely aspartic acid, glutamic acid and GABA, showed lower concentrations than in normal brain. Some amino acids were in the same concentration as in normal brain: taurine, phosphoethanolamine, glutamine and cystathionine. Most of the others were in higher concentrations than in normal brain, mainly proline. The results suggest that the concentrations of 5 compounds: taurine, proline, cystathionine, GABA and homocarnosine, taken as a whole, provide information on the origin of the sample.