[Biosynthesis of amino acids from glucose in the central nervous system in the Parkinson syndrome].

The incorporation of labelled carbon from glucose U-14C into CSF amino acids was investigated in three patients with Parkinson's disease and in three control persons with comparable age and physical stature. Comparing the specific radioactivities of serum and CSF one can postulate that the labelled amino acids found in the CSF are synthesized mainly by brain tissue. The resorption of glucose into the CNS and therefore the synthesis of amino acids from glucose was more rapid in controls; labelled alanine and glutamine appeared later in the CSF of the patients. As expected, in the controls the specific radioactivity of glutamic acid was found to be higher than that of glutamine, in patients the labelling of glutamine was higher as was that of serine, glycine, aspartic acid and asparagine. From our knowledge concerning the compartmentation of the metabolism of glutamate, we assume that in Parkinsonism the metabolic activity of neurons is reduced but that of astroglia is enhanced.