Amplitude and frequency modulation of pulsatile luteinizing hormone-releasing hormone release

Jon E. Levine, Patrick Chappell, Leslie M. Besecke, Angela C. Bauer-Dantoin, Andrew M. Wolfe, Tarja Porkka-Heiskanen, Janice H. Urban

Research output: Contribution to journalArticlepeer-review

34 Scopus citations


1. A variety of neuroendocrine approaches has been used to characterize cellular mechanisms governing luteinizing hormone-releasing hormone (LHRH) pulse generation. We review recent in vivo microdialysis, in vitro superfusion, and in situ hybridization experiments in which we tested the hypothesis that the amplitude and frequency of LHRH pulses are subject to independent regulation via distinct and identifiable cellular pathways. 2. Augmentation of LHRH pulse amplitude is proposed as a central feature of preovulatory LHRH surges. Three mechanisms are described which may contribute to this increase in LHRH pulse amplitude: (a) increased LHRH gene expression, (b) augmentation of facilitatory neurotransmission, and (c) increased responsiveness of LHRH neurons to afferent synaptic signals. Neuropeptide Y (NPY) is examined as a prototypical afferent transmitter regulating the generation of LHRH surges through the latter two mechanisms. 3. Retardation of LHRH pulse generator frequency is postulated to mediate negative feedback actions of gonadal hormones. Evidence supporting this hypothesis is reviewed, including results of in vivo monitoring experiments in which LHRH pulse frequency, but not amplitude, is shown to be increased following castration. A role for noradrenergic neurons as intervening targets of gonadal hormone negative feedback actions is discussed. 4. Future directions for study of the LHRH pulse generator are suggested.

Original languageEnglish (US)
Pages (from-to)117-139
Number of pages23
JournalCellular and molecular neurobiology
Issue number1
StatePublished - Feb 1995


  • gonadal hormones
  • hypothalamus
  • luteinizing hormone
  • luteinizing hormone-releasing hormone
  • neuropeptide Y
  • neurosecretion
  • norepinephrine
  • pituitary
  • pulses
  • surges

ASJC Scopus subject areas

  • Cellular and Molecular Neuroscience
  • Cell Biology


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