Isolation and Characterization of a GnRH-like Peptide from Octopus vulgaris

• Published in: Biochemical and biophysical research communications Vol. 291; no. 5; pp. 1187 - 1193
• Main Authors: Iwakoshi, Eiko, Takuwa-Kuroda, Kyoko, Fujisawa, Yuko, Hisada, Miki, Ukena, Kazuyoshi, Tsutsui, Kazuyoshi, Minakata, Hiroyuki
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15.03.2002
• Subjects: Amino Acid Sequence; Animals; Base Sequence; cDNA cloning; Central Nervous System; DNA, Complementary - analysis; ELISA; Gonadotropin-Releasing Hormone - biosynthesis; Gonadotropin-Releasing Hormone - genetics; Gonadotropin-Releasing Hormone - isolation & purification; Immunohistochemistry; Molecular Sequence Data; Octopodiformes - chemistry; Octopodiformes - genetics; octopus GnRH; Octopus vulgaris; Peptides - genetics; Peptides - isolation & purification; RT-PCR Southern blot analysis; TOF-MS; TOF-MS; cDNA cloning; RT-PCR Southern blot analysis; immunohistochemistry; octopus GnRH; ELISA
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1006/bbrc.2002.6594

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.