title: Isolation and characterization of a GnRH-like peptide from Octopus vulgaris.
abstract: Gonadotropin-releasing hormone (GnRH) is the key peptide in the hypothalamo-hypophysial-gonadal axis, the core of regulation of reproduction in vertebrates. In this study, an octopus peptide with structural features similar to vertebrate GnRHs was isolated from brains of Octopus vulgaris. This peptide showed luteinizing hormone-releasing activity in quail anterior pituitary cells. A cDNA encoding the precursor protein was cloned. The RT-PCR transcripts were expressed in the supraesophageal and subesophageal brains, peduncle complex, and optic gland. The presence of the peptide in the different brain region was confirmed with enzyme-linked immunosorbent assay and time-of-flight mass spectrometric analysis. Immunoreactive neuronal cell bodies and fibers were observed in the subpedunculate lobe that controls the optic-gland activity. Optic gland nerves and glandular cells in the optic gland were immunostained. The isolated peptide may be octopus GnRH that contributes to octopus reproduction not only as a neurohormone but also as an endocrine hormone.
authors.affiliation: Suntory Institute for Bioorganic Research, 1-1-1 Wakayamadai, Shimamoto, Mishima, Osaka 618-8503, Japan.
authors.forename: Eiko
authors.initials: E
authors.lastname: Iwakoshi
authors.forename: Kyoko
authors.initials: K
authors.lastname: Takuwa-Kuroda
authors.forename: Yuko
authors.initials: Y
authors.lastname: Fujisawa
authors.forename: Miki
authors.initials: M
authors.lastname: Hisada
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Ukena
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Tsutsui
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Minakata
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002490:Central Nervous System; D018076:DNA, Complementary / Q000032:analysis; D007987:Gonadotropin-Releasing Hormone / Q000096:biosynthesis / Q000235:genetics / Q000302:isolation & purification*; D007150:Immunohistochemistry; D008969:Molecular Sequence Data; D049831:Octopodiformes / Q000737:chemistry* / Q000235:genetics; D010455:Peptides / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D018076:DNA, Complementary; C045152:Gonadorelin-like peptides; D010455:Peptides; D007987:Gonadotropin-Releasing Hormone