Identification, expression, and physiological functions of Siberian hamster gonadotropin-inhibitory hormone

Takayoshi Ubuka, Kazuhiko Inoue, Yujiro Fukuda, Takanobu Mizuno, Kazuyoshi Ukena, Lance J. Kriegsfeld, Kazuyoshi Tsutsui*

*この研究の対応する著者

    研究成果: Article査読

    228 被引用数 (Scopus)

    抄録

    Gonadotropin-inhibitory hormone (GnIH) is a hypothalamic neuropeptide that inhibits gonadotropin secretion in birds and mammals. To further understand its physiological roles in mammalian reproduction, we identified its precursor cDNA and endogenous mature peptides in the Siberian hamster brain. The Siberian hamster GnIH precursor cDNA encoded two RFamide-related peptide (RFRP) sequences. SPAPANKVPHSAANLPLRF-NH 2 (Siberian hamster RFRP-1) and TLSRVPSLPQRFNH 2 (Siberian hamster RFRP-3) were confirmed as mature endogenous peptides by mass spectrometry from brain samples purified by immunoaffinity chromatography. GnIH mRNA expression was higher in long days (LD) compared with short days (SD). GnIH mRNA was also highly expressed in SD plus pinealectomized animals, whereas expression was suppressed by melatonin, a nocturnal pineal hormone, administration. GnIH-immunoreactive (-ir) neurons were localized to the dorsomedial region of the hypothalamus, and GnIH-ir fibers projected to hypothalamic and limbic structures. The density of GnIH-ir perikarya and fibers were higher in LD and SD plus pinealectomized hamsters than in LD plus melatonin or SD animals. The percentage of GnRH neurons receiving close appositions from GnIH-ir fiber terminals was also higher in LD than SD, and GnIH receptor was expressed in GnRH-ir neurons. Finally, central administration of hamster RFRP-1 or RFRP-3 inhibited LH release 5 and 30 min after administration in LD. In sharp contrast, both peptides stimulated LH release 30 min after administration in SD. These results suggest that GnIH peptides fine tune LH levels via its receptor expressed in GnRH-ir neurons in an opposing fashion across the seasons in Siberian hamsters.

    本文言語English
    ページ(範囲)373-385
    ページ数13
    ジャーナルEndocrinology
    153
    1
    DOI
    出版ステータスPublished - 2012 1月

    ASJC Scopus subject areas

    • 内分泌学

    フィンガープリント

    「Identification, expression, and physiological functions of Siberian hamster gonadotropin-inhibitory hormone」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。

    引用スタイル