Review: Melatonin stimulates the synthesis and release of gonadotropin-inhibitory hormone in birds

Vishwajit S. Chowdhury, Takayoshi Ubuka, Kazuyoshi Tsutsui

    Research output: Contribution to journalArticle

    25 Citations (Scopus)

    Abstract

    Gonadotropin-inhibitory hormone (GnIH), a neuropeptide that inhibits gonadotropin synthesis and release, was first identified in the quail hypothalamus. To understand the physiological role of GnIH, this review will demonstrate the mechanisms that regulate GnIH synthesis and release. Pinealectomy (Px) combined with orbital enucleation (Ex) decreased the synthesis of GnIH precursor mRNA and content of mature GnIH peptide in the diencephalon. Melatonin administration to Px plus Ex birds caused a dose-dependent increase in the synthesis of GnIH precursor mRNA and production of mature peptide. A melatonin receptor subtype, Mel1c, was expressed in GnIH-immunoreactive neurons, suggesting direct action of melatonin on GnIH neurons. Melatonin administration further increased GnIH release in a dose-dependent manner from hypothalamic explants in vitro. GnIH mRNA expression and GnIH release during the dark period were greater than those during the light period in explants from quail exposed to long-day photoperiods. Conversely, plasma luteinizing hormone (LH) concentration decreased during the dark period. This review summarizes that melatonin appears to act on GnIH neurons in stimulating not only GnIH synthesis but also its release, thus inhibiting plasma LH concentration in birds.

    Original languageEnglish
    Pages (from-to)175-178
    Number of pages4
    JournalGeneral and Comparative Endocrinology
    Volume181
    Issue number1
    DOIs
    Publication statusPublished - 2013 Jan 5

    Keywords

    • Birds
    • Gonadotropin-inhibitory hormone
    • Hypothalamus
    • Luteinizing hormone
    • Melatonin

    ASJC Scopus subject areas

    • Endocrinology

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