THE METABOLISM IN VIVO OF GLYCINE AND SERINE IN EIGHT AREAS OF THE RAT CENTRAL NERVOUS SYSTEM

Authors

  • R. P Shank,

    1. Section of Neurobiology, The Institute of Psychiatric Research and Departments of Biochemistry and Psychiatry, Indiana University Medical Center, Indianapolis, Indiana 46202
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  • M. H Aprison

    1. Section of Neurobiology, The Institute of Psychiatric Research and Departments of Biochemistry and Psychiatry, Indiana University Medical Center, Indianapolis, Indiana 46202
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  • 1 This investigation was supported in part by Research Grant NB-07307-03 from the National Institute of Health, Research Grant MH-03225-11 and Postdoctoral Training Grant MH-10695-04 from the National Institute of Mental Health, U.S. Public Health Service.

Abstract

Abstract— Results of studies designed to estimate the rates at which glycine is derived from various possible sources in discrete areas of the rat CNS are reported. These results suggest that glycine is derived predominantly by de novo synthesis, presumably via the established pathways leading from glucose through serine to glycine. The content of glycine ranged from a low of approximately 0-6 μmol/g in the cerebellum and telencephalon to a high of 5·5 μmol/g in the spinal cord grey matter; however, based on its estimated rate of synthesis from serine, there appeared to be no correlation between the content of glycine and its rate of synthesis in the various areas studied. The flux of glycine from blood into the CNS was slower (0·03-0·15 μmol/g/h depending on the CNS structure) than that of serine (0·15-0·23 μmol/g/h) and both amino acids entered various CNS areas at rates unrelated to their respective tissue contents. These data have been discussed with regard to the putative transmitter function of glycine in the spinal cord and brainstem.

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