Journal of Comparative Physiology A

, Volume 161, Issue 2, pp 315–319 | Cite as

Evidence for a daily rhythmicity in the acute release of luteinizing hormone in response to electrical stimulation in the Japanese quail

  • H. Konishi
  • R. G. Foster
  • B. K. Follett
Article

Summary

This study was undertaken to examine the effect of electrical stimulation of the hypothalamus at different times of day on luteinizing hormone (LH) secretion in male castrated quail on short days (8L∶16D). The posterior hypothalamus was stimulated with square-wave pulses of 80 μA for 2 min through chronically-implanted platinum microelectrodes. Stimulation was carried out on each quail at 4 (treatment A), 10 (B), or 14 h (C) after dawn. Plasma LH levels were increased markedly within 2 min of ending the stimulation but reached basal levels again over the next 20 min or so. The absolute increase was significantly greater in treatment B (10 h after lights on) than at the other times tested. This is consistent with a rhythm in hypothalamic responsivity. The results are discussed in the context of the rhythm of photoinducibility which occurs early in the night and which is used by quail as a photoperiodic clock to regulate seasonal reproduction.

Abbreviations

LH

luteinizing hormone

LH-RH

luteinizing hormone-releasing hormone

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References

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Copyright information

© Springer-Verlag 1987

Authors and Affiliations

  • H. Konishi
    • 1
  • R. G. Foster
    • 1
  • B. K. Follett
    • 1
  1. 1.AFRC Research Group on Photoperiodism and Reproduction, Department of ZoologyUniversity of BristolBristolUK

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