Characterization of a cDNA encoding a novel avian hypothalamic neuropeptide exerting an inhibitory effect on gonadotropin release

H. Satake, M. Hisada, T. Kawada, H. Minakata, K. Ukena, Kazuyoshi Tsutsui

Research output: Contribution to journalArticle

163 Citations (Scopus)

Abstract

We previously isolated a novel dodecapeptide containing a C-terminal -Arg-Phe-NH2 sequence. SIKPSAYLPLRF-NH2 (RFamide peptide), from the quail brain. This quail RFamide peptide was shown to decrease gonadotropin release from the cultured anterior pituitary and to be located at least in the quail hypothalamo-hypophysial system. We therefore designated this RFamide peptide gonadotropin inhibitory hormone (GnIH). In the present study we characterized the GnIH cDNA from the quail brain by a combination of 3′ and 5′ rapid amplification of cDNA ends ('RACE'). The deduced GnIH precursor consisted of 173 amino acid residues, encoding one GnIH and two putative gene-related peptide (GnIH-RP-1 and GnIH-RP-2) sequences that included -LPXRF (X = L or Q) at their C-termini. All these peptide sequences were flanked by a glycine C-terminal amidation signal and a single basic amino acid on each end as an endoproteolytic site. Southern blotting analysis of reverse-transcriptase-mediated PCR products demonstrated a specific expression of the gene encoding GnIH in the diencephalon including the hypothalamus. Furthermore, mass spectrometric analyses detected the mass numbers for matured GnIH and GnIH-RP-2, revealing that both peptides are produced from the precursor in the diencephalon as an endogenous ligand. Taken together, these results lead to the conclusion that GnIH is a hypothalamic factor responsible for the negative regulation of gonadotropin secretion. Furthermore, the presence of a novel RFamide peptide family containing a C-terminal -LPXRF-NH2 sequence has been revealed.

Original languageEnglish
Pages (from-to)379-385
Number of pages7
JournalBiochemical Journal
Volume354
Issue number2
DOIs
Publication statusPublished - 2001 Mar 1
Externally publishedYes

Keywords

  • Gonadotropin inhibitory hormone
  • Mass spectrometry
  • Quail

ASJC Scopus subject areas

  • Biochemistry

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