Utilization of [15N]glutamate by cultured astrocytes

M. Yudkoff, I. Nissim, K. Hummeler, M. Medow, David E Pleasure

Research output: Contribution to journalArticle

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Abstract

The metabolism of 0.25 mM-[15N]glutamic acid in cultured astrocytes was studied with gas chromatography-mass spectrometry. Almost all 15N was found as [2-15N]glutamine, [5-15N]glutamine and [15N]alanine after 210 min of incubation. Some incorporation of 15N into aspartate and the 6-amino position of the adenine nucleotides also was observed, the latter reflecting activity of the purine nucleotide cycle. After the addition of [15N]glutamate the ammonia concentration in the medium declined, but the intracellular ATP concentration was unchanged despite concomitant ATP consumption in the glutamine synthetase reaction. Some potential sources of glutamate nitrogen were identified by incubating the astrocytes for 24 h with [5-15N]glutamine, [2-15N]glutamine or [15N]alanine. Significant labeling of glutamate was noted with addition of glutamine labelled on either the amino or the amide moiety, reflecting both glutaminase activity and reductive amination of 2-oxoglutarate in the glutamate dehydrogenase reaction. Alanine nitrogen also is an important source of glutamate nitrogen in this system.

Original languageEnglish (US)
Pages (from-to)185-192
Number of pages8
JournalBiochemical Journal
Volume234
Issue number1
StatePublished - 1986
Externally publishedYes

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Glutamine
Astrocytes
Glutamic Acid
Alanine
Nitrogen
Adenosine Triphosphate
Glutaminase
Purine Nucleotides
Amination
Glutamate Dehydrogenase
Glutamate-Ammonia Ligase
Adenine Nucleotides
Ammonia
Metabolism
Aspartic Acid
Amides
Gas chromatography
Gas Chromatography-Mass Spectrometry
Labeling
Mass spectrometry

ASJC Scopus subject areas

  • Biochemistry

Cite this

Yudkoff, M., Nissim, I., Hummeler, K., Medow, M., & Pleasure, D. E. (1986). Utilization of [15N]glutamate by cultured astrocytes. Biochemical Journal, 234(1), 185-192.

Utilization of [15N]glutamate by cultured astrocytes. / Yudkoff, M.; Nissim, I.; Hummeler, K.; Medow, M.; Pleasure, David E.

In: Biochemical Journal, Vol. 234, No. 1, 1986, p. 185-192.

Research output: Contribution to journalArticle

Yudkoff, M, Nissim, I, Hummeler, K, Medow, M & Pleasure, DE 1986, 'Utilization of [15N]glutamate by cultured astrocytes', Biochemical Journal, vol. 234, no. 1, pp. 185-192.
Yudkoff M, Nissim I, Hummeler K, Medow M, Pleasure DE. Utilization of [15N]glutamate by cultured astrocytes. Biochemical Journal. 1986;234(1):185-192.
Yudkoff, M. ; Nissim, I. ; Hummeler, K. ; Medow, M. ; Pleasure, David E. / Utilization of [15N]glutamate by cultured astrocytes. In: Biochemical Journal. 1986 ; Vol. 234, No. 1. pp. 185-192.
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