Amino Acids

, Volume 6, Issue 1, pp 47–56 | Cite as

Excitatory amino acids as modulators of gonadotropin secretion

  • M. Zanisi
  • E. Messi
  • M. Galbiati
Article
  • 19 Downloads

Summary

The effects of quinolinic acid (QUIN) and quisqualate (QA) on the secretion of GnRH from MBH and LH and FSH from AP of 50 day old male rats have been evaluated by means of an “in vitro” perifusion technique.

QUIN (100µM) is able to increase GnRH secretion with an action mediated by an NMDA receptor type, as shown by the inhibitory effect exerted by both a competitive (AP-5) and a non-competitive (MK-801) specific antagonist.

QA “per se” at the concentrations tested (1–100µM) does not modify GnRH and gonadotropin secretion, but in the presence of a specific KA/QA receptor antagonist (DNQX) exerts a stimulatory effect at both levels.

This observation might indicate that of the two QA receptor subtypes (ionotropic and metabotropic), this agonist binds to the metabotropic one with very low affinity: thus it is likely that a higher dose is required in order to have any effect on gonadotropin secretion. However, in the presence of DNQX, which binds to the ionotropic receptor, all the available QA can bind to the metabotropic one and can exert its action at MBH AP levels.

Keywords

Amino acids EAA GnRH LH FSH Hypothalamus Pituitary 

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References

  1. Arslan M, Pohl CR, Plant TM (1988) DL-2-amino-5-phosphonopentanoic acid, a specific N-methyl-D-aspartic acid receptor antagonist, suppresses pulsatile LH release in the rat. Neuroendocrinology 47: 465–468Google Scholar
  2. Bettler B, Boulter J, Hermans-Borgmeyer I, O'Shea-Greenfield A, Deneris E, Moll C, Borgmeyer U, Hollmann M, Heinemann S (1990) Cloning of a novel glutamate receptor subunit, GluR5: expression in the central nervous system during development. Neuron 5: 583–595Google Scholar
  3. Bourguignon JP, Gerard A, Franchimont P (1989) Direct activation of gonadotropinreleasing hormone secretion through different receptors to neuroexcitatory amino acids. Neuroendocrinology 49: 402–408Google Scholar
  4. Cicero TJ, Meyer ER, Bel RD (1988) Characterization and possible opioid modulation of N-methyl-D-aspartic acid induced increases in serum luteinizing hormone levels in the developing male rat. Life Sci 42: 1725–1732Google Scholar
  5. Donoso AO, Lopez FJ, Negro-Vilar A (1990) Glutamate recptors of the non-N-methyl-D-aspartic acid type mediate the increase in luteinizing hormone-releasing hormone release by excitatory aminoacid “in vitro”. Endocrinology 126: 414–420Google Scholar
  6. Foster AC, Schwarcz R (1984) Synthesis of quinolinic acid by 3-hydroxyanthranilic acid oxygenase in rat brain tissue. Soc Neurosci Abstr 10Google Scholar
  7. Gay VL, Plant TM (1987) N-Methyl-D,L-aspartate elicits hypothalamic gonadotropinreleasing hormone release in prepubertal male rhesus monkeys. Endocrinology 120: 2289–2296Google Scholar
  8. Honoré T, Davies SN, Drejer J, Fletcher EJ, Jacobsen P, Lodge D, Nielsen FE (1988) Quinoxalinediones: potent competitive non-NMDA glutamate receptor antagonists. Science 241: 701–703Google Scholar
  9. Leranth C, Segura LMG, Palkovitz M, MacLusky NJ, Shanabrough M, Naftolin F (1988) The LHRH-containing neural network in the preoptic area of the rat: demonstration of LHRH-containing nerve terminals in synaptic contact with LHRH neurons. Brain Res 354: 332–336Google Scholar
  10. Lopez FJ, Donoso AO, Negro-Vilar A (1992) Endogenous excitatory aminoacids and glutamate receptor subtypes involved in the control of hypotalamic luteinizing hormonereleasing hormone secretion. Endocrinology 130: 1986–1992Google Scholar
  11. Moroni F, Russi P, Lombardi G, Beni M, Carla V (1988) Presence of kynurenic acid in the mammalian brain. J Neurochem 51: 177Google Scholar
  12. Nawy S, Jahr CE (1990) Suppression by glutamate of cGMP-activated conductance in retinal bipol cells. Nature 346: 269–271Google Scholar
  13. Nemeroff CB, Mason GA, Bissette G, Parks DA, Schwarcz R (1985) Effect of intrahypotalamic injection of quinolinic acid on anterior pituitary hormone secretion in the unanesthetized rat. Neuroendocrinology 41: 332–336Google Scholar
  14. Ondo JG, Pass KA, Baldwin R (1976) The effects of neurally active aminoacids on pituitary gonadotropin secretion. Neuroendocrinology 21: 79–87Google Scholar
  15. Perkins MN, Stone TC (1983) Pharmacology and regional variations of quinolinic acidevoked excitations in the rat central nervous system. J Pharmacol Exp Ther 226: 551–557Google Scholar
  16. Price MT, Olney JW, Cicero TJ (1978) Acute elevations of serum luteinizing hormone induced by kainic acid, N-methyl aspartic acid or homocysteic acid. Neuroendocrinology 26: 352–358Google Scholar
  17. Price MT, Olney JW, Anglim M, Buchsbaum S (1979) Reversible action of N-methyl aspartate on gonadotrophin neuroregulation. Brain Res 176: 165–168Google Scholar
  18. Recasens M, Guiramand J, Novrigata, Sassetti I, Devilliers G (1988) A new quisqualate receptor subtype (sAA2) responsible for the glutamate-induced inositol phosphate formation in rat brain synaptoneurosomes. Neurochem Int 13: 463–467Google Scholar
  19. Schainker BA, Cicero TJ (1980) Acute central stimulation of luteinizing hormone by parenterally administred N-methyl-D,L-aspartic acid in the male rat. Brain Res 184: 425–437Google Scholar
  20. Schwarcz R, Foster AC, Iwai K (1983) Quinolinic acid phosphoribosyl transferase in rat brain. Soc Neurosci Abstr 9Google Scholar
  21. Schwarcz R, Foster AC, French ED, Whetsell WO Jr, Hohler C (1984) Excitotoxic models for neurodegenerative disorders. Life Sci 35: 19–32Google Scholar
  22. Thio LL, Clifford DB, Zorumski CF (1991) Characterization of quisqualate receptor desensitization in cultured postnatal rat hippocampal neurons. J Neurosci 11: 3430–3441Google Scholar
  23. Urbanski HF, Ojeda SR (1987) Activation of luteinizing hormone-releasing hormone release advances the onset of female puberty. Neuroendocrinology 46: 273–276Google Scholar
  24. Wolfensberger M, Amsler U, Cuenod M, Foster A, Schwarcz R (1983) Identification of quinolinic acid in rat and human brain tissue. Neurosci Lett 41: 247–252Google Scholar
  25. Yool AJ, Krieger RM, Gruol DL (1992) Multiple ionic mechanisms are activated by the potent agonist quisqualate in cultured cerebellar Purkinje neurons. Brain Res 573: 83–94Google Scholar
  26. Zanisi M, Messi E (1991) Sex steroids and the control of LHRH secretion. J Steroid Biochem Mol Biol 40: 155–163Google Scholar
  27. Zanisi M, Messi E, Motta M, Martini L (1987) Ultrashort feedback control of luteinizing hormone-releasing hormone secretion in vitro. Endocrinology 121: 2199–2204Google Scholar

Copyright information

© Springer-Verlag 1994

Authors and Affiliations

  • M. Zanisi
    • 1
  • E. Messi
    • 1
  • M. Galbiati
    • 1
  1. 1.Department of EndocrinologyUniversity of MilanMilanoItaly

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