Melatonin stimulates the release of gonadotropin-inhibitory hormone by the avian hypothalamus

Vishwajit S. Chowdhury, Kazutoshi Yamamoto, Takayoshi Ubuka, George E. Bentley, Atsuhiko Hattori, Kazuyoshi Tsutsui*

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    126 Citations (Scopus)


    Gonadotropin-inhibitory hormone (GnIH), a neuropeptide that inhibits gonadotropin synthesis and release, was first identified in quail hypothalamus. GnIH acts on the pituitary and GnRH neurons in the hypothalamus via GnIH receptor to inhibit gonadal development and maintenance. In addition, GnIH neurons express melatonin receptor and melatonin induces GnIH expression in the quail brain. Thus, it seems that melatonin is a key factor controlling GnIH neural function. In the present study, we investigated the role of melatonin in the regulation of GnIH release and the correlation of GnIH release with LH release in quail. Melatonin administration dose-dependently increased GnIH release from hypothalamic explants in vitro. GnIH release was photoperiodically controlled. A clear diurnal change in GnIH release was observed in quail, and this change was negatively correlated with changes in plasma LH concentrations. GnIH release during the dark period was greater than that during the light period in explants from quail exposed to long-day photoperiods. Conversely, plasma LH concentrations decreased during the dark period. In contrast to LD, GnIH release increased under short-day photoperiods, when the duration of nocturnal secretion of melatonin increases. These results indicate that melatonin may play a role in stimulating not only GnIH expression but also GnIH release, thus inhibiting plasma LH concentrations in quail. This is the first report describing the effect of melatonin on neuropeptide release.

    Original languageEnglish
    Pages (from-to)271-280
    Number of pages10
    Issue number1
    Publication statusPublished - 2010 Jan

    ASJC Scopus subject areas

    • Endocrinology


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