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Estrogen (17β-Estradiol) Enhances Glutamine Synthetase Activity in C6-Glioma Cells

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Glutamine synthetase (GS) is the major glutamine-forming enzyme of vertebrates and is accepted to be a marker of astroglial cells. Maturation of astroglial cells is characterized by an increase of GS activity, and the regulation of this enzyme is the topic of many publications. Because of the fundamental role of the GS in controlling brain glutamate and glutamine level, it is essential to understand the mechanism of expression of this enzyme. To our knowledge, the effect of estrogen (17β-estradiol) on GS activity in glial cells has not been reported. We examined the effect of treatment with estrogen on glutamine synthetase enzyme activity in glial cells. C6-glioma cells in later passage have many astrocytic characteristics and provided a convenient and well-established model system. We adapted a colorimetric method to measure GS-catalyzed γ-glutamyltransferase (GT) activity in C6-glioma cells. The assay monitors GT activity of glutamine synthetase by following the absorbance of the product γ-glutamyl hydroxamate at 540 nm. We observed that, the absorbance of γ-glutamyl hydroxamate significantly increased in estrogen treated cells (0.13±0.03), as compared to untreated cells (0.058±0.015). Estrogen also significantly increased concentration of glutamine in C6-glioma cells as measured by fluorometric assay. In addition, western blot analysis showed that estrogen significantly increased the amount of glutamine synthetase compared to control. This estrogen effect could have important physiological implications on cerebral glutamate and glutamine metabolism.

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  1. 1.

    B. S. Meldrum (2000) ArticleTitleGlutamate as a neurotransmitter in the brain: review of physiology and pathology J. Nutr. 130 1007S–1015S Occurrence Handle10736372

  2. 2.

    D. W. Chio (1988) ArticleTitleGlutamate neurotoxicity and diseases of the nervous system Neuron 1 IssueID8 623–634 Occurrence Handle10.1016/0896-6273(88)90162-6 Occurrence Handle2908446

  3. 3.

    D. W. Choi S. M. Rothman (1990) ArticleTitleThe role of glutamate neurotoxicity in hypoxic-ischemic neurons death Annu. Rev. Neurosci. 13 171–182 Occurrence Handle10.1146/ Occurrence Handle1970230

  4. 4.

    W. O. Whetsell SuffixJr. N. A. Shapira (1993) ArticleTitleNeuroexcitation, excitotoxicity and human neurological disease Lab. Invest. 68 372–387 Occurrence Handle8479146

  5. 5.

    J. D. Clements R. A. J. Lester G. Tong C. E. Jahr G. L. Westbrook (1992) ArticleTitleThe time course of glutamate in the synaptic cleft Science 258 1498–1501 Occurrence Handle1359647

  6. 6.

    M. D. Norenberg A. Martinez-Hernandez (1979) ArticleTitleFine structural localization of glutamine synthetase in astrocytes of rat brain Brain Res. 161 303–310 Occurrence Handle10.1016/0006-8993(79)90071-4 Occurrence Handle31966

  7. 7.

    I. Shaked I. Ben-Dror L. Vardimon (2002) ArticleTitleGlutamine synthetase enhances the clearance of extracellular glutamate by the neural retina J. Neurochem. 83 574–580 Occurrence Handle10.1046/j.1471-4159.2002.01168.x Occurrence Handle12390519

  8. 8.

    L. Hertz R. Dringen A. Schouboe S. R. Robinson (1999) ArticleTitleAstrocytes: glutamate producers for neurons J. Neurosci. Res. 57 417–428 Occurrence Handle10.1002/(SICI)1097-4547(19990815)57:4<417::AID-JNR1>3.0.CO;2-N Occurrence Handle10440891

  9. 9.

    C. J. Van der Berg D. Garfinkel (1971) ArticleTitleA stimulation study of brain compartments. Metabolism of glutamine and related substances in mouse brain Biochem. J. 123 211–218 Occurrence Handle5164952

  10. 10.

    L. A. J. Kennedy M. J. Voaden J. Marshall (1974) ArticleTitleGlutamate metabolism in the frog retina Nature (London) 252 50–52

  11. 11.

    S. R. Max J. Mill K. Mearow M. Konagaya Y. Konagaya J. W. Thomas C. Banner L. Vitkovic’ (1988) ArticleTitleDexamethasone regulates glutamine synthetase expression in rat skeletal muscles Am. J. Physiol. 255 E397–E403 Occurrence Handle2901814

  12. 12.

    C. J. Santoro G. Harris A. Sitlani (2001) ArticleTitleColormetric detection of glutamine synthetase catalyzed transferase activity in glucocorticoid-treated skeletal muscle cells Anal. Biochem. 289 18–25 Occurrence Handle10.1006/abio.2000.4911 Occurrence Handle11161290

  13. 13.

    B. Bhandari D. M. Burns R. C. Hoffman R. E. Miller (1986) ArticleTitleGlutamine synthetase mRNA in cultured 3T3-L1 adipocytes. Complexity, content and hormonal regulation Mol. Cell. Endocrinol. 47 49–57 Occurrence Handle10.1016/0303-7207(86)90015-8 Occurrence Handle2875005

  14. 14.

    K. Hallermayer C. Harmening B. Hamprecht (1981) ArticleTitleCellular localization and regulation of glutamine synthetase in primary cultures of brain cells from newborn mice J. Neurochem. 37 43–52 Occurrence Handle6114136

  15. 15.

    A. J. Patel A. Hunt (1985) ArticleTitleObservations on cell growth regulation of glutamine synthetase by dexamethasone in primary cultures of forebrain and cerebellar astrocytes Dev. Brain Res. 18 175–184 Occurrence Handle10.1016/0165-3806(85)90262-7

  16. 16.

    M. R. Pishak A. T. Phillips (1980) ArticleTitleGlucocorticoid stimulation of glutamine synthetase production in cultured rat glioma cells J. Neurochem. 34 866–872 Occurrence Handle6102113

  17. 17.

    L. Verdier Y. Boirie S. Van Drieesche M. Mignon R. J. Begue D. Meynial-Denis (2002) ArticleTitleDo sex steroids regulate glutamine synthesis with age? Am. J. Physiol. Endocrinol. Metab. 282 IssueID1 E215–221 Occurrence Handle11739103

  18. 18.

    O. H. Lowry J. V. Passonneau (1972) A Flexible System of Enzymatic Analysis Academic Press New York, San Francisco, and London

  19. 19.

    P. K. Smith R. I. Krohn G. T. Hermanson A. K. Mallia F. H. Gartner M. D. Provenzano (1985) ArticleTitleMeasurement of protein using bicinchoninic acid Anal. Biochem. 150 76–85 Occurrence Handle10.1016/0003-2697(85)90442-7 Occurrence Handle3843705

  20. 20.

    S. Seigle (1956) Nonparametric statistics for the behavioral sciences McGraw-Hill New York

  21. 21.

    L. I. McKay D. C. DuBois Y. N. Sun R. R. Almon W. J. Jusko (1997) ArticleTitleCorticosteroid effects in skeletal muscle: gene induction/receptor autoregulation Muscle Nerve 20 IssueID10 1318–1320 Occurrence Handle10.1002/(SICI)1097-4598(199710)20:10<1318::AID-MUS17>3.0.CO;2-Z Occurrence Handle9324091

  22. 22.

    S. R. Max (1990) ArticleTitleGlucocorticoid-mediated induction of glutamine synthetase in skeletal muscle Med. Sci. Sports Exercise 22 325–330

  23. 23.

    Y. N. Sun L. I. McKay D. C. DuBois W. J. Jusko R. R. Almon (1999) ArticleTitlePharmacokinetic/pharmacodynamic models for corticosteroid receptor down-regulation and glutamine synthetase induction in rat skeletal muscle by a receptor/gene-mediated mechanism J. Pharmacol. Exp. Ther. 288 720–728 Occurrence Handle9918581

  24. 24.

    M. Weibel B. Pettmann G. Labourdette M. Miehe E. Boch M. Sensenbrenner (1985) ArticleTitleMorphological and biochemical maturation of rat astroglial cells grown in a chemically defined medium: Influence of an astroglial growth factor Int. J. Dev. Neurosci. 3 617–630 Occurrence Handle10.1016/0736-5748(85)90052-8

  25. 25.

    S. Santagati R. C Melcangi R. C. F. Celotti L. Martini A. Maggi (1994) ArticleTitleEstrogen receptor is expressed in different types of glial cells in culture J. Neurochem. 63 2058–2064 Occurrence Handle7964723

  26. 26.

    P. J. Shughrue B. Komm J. Merchenthaler (1996) ArticleTitleThe distribution of estrogen receptor β mRNA in the rat hypothalamus Steroids 61 678–681 Occurrence Handle10.1016/S0039-128X(96)00222-X Occurrence Handle8987135

  27. 27.

    I. Azcoitia A. sierra L. M. Garcia-Segura (1999) ArticleTitleLocalization of estrogen receptor beta-immunoreactivity in astrocytes of the adult rat brain Glia 26 IssueID3 260–267 Occurrence Handle10.1002/(SICI)1098-1136(199905)26:3<260::AID-GLIA7>3.0.CO;2-R Occurrence Handle10340766

  28. 28.

    C. D. Buchanan V. B. Mahesh D. W. Brann (2000) ArticleTitleEstrogen astrocyte-luteinizing hormone releasing hormone signaling: a role for transforming growth factor-beta (1) Biol. Reprod. 62 IssueID6 1710–1721 Occurrence Handle10819775

  29. 29.

    E. Hosli K. Jurasin W. Ruhl R. Luthy L. Hosli (2001) ArticleTitleColocalization of androgen, estrogen and cholinergic receptors on cultured astrocytes of rat central nervous system Int. J. Dev. Neurosci. 19 IssueID1 11–19 Occurrence Handle10.1016/S0736-5748(00)00082-4 Occurrence Handle11226751

  30. 30.

    J. D. Su Y. P. Zhong X. Y. Li J. W. Wang Y. Z. Chen (2001) ArticleTitleExpression of estrogen receptor (ER)-alpha and beta immunoreactivity in hippo-campal cell cultures with special attention to GABA ergic neurons J. Neurosci. Res. 65 IssueID5 396–402 Occurrence Handle10.1002/jnr.1166 Occurrence Handle11536322

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Correspondence to N. Haghighat.

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Haghighat, N. Estrogen (17β-Estradiol) Enhances Glutamine Synthetase Activity in C6-Glioma Cells. Neurochem Res 30, 661–667 (2005).

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  • Glutamine synthetase
  • estrogen
  • astrocytes
  • C6-glioma cells