Novel fish hypothalamic neuropeptides stimulate the release of gonadotrophins and growth hormone from the pituitary of sockeye salmon

• Published in: Journal of endocrinology Vol. 188; no. 3; pp. 417 - 423
• Main Authors: Amano, Masafumi, Moriyama, Shunsuke, Iigo, Masayuki, Kitamura, Shoji, Amiya, Noriko, Yamamori, Kunio, Ukena, Kazuyoshi, Tsutsui, Kazuyoshi
• Format: Journal Article
• Language: English
• Published: Colchester BioScientifica 01.03.2006; Portland Press
• Subjects: Animals; Biological and medical sciences; Carassius auratus; Cells, Cultured; Fish Proteins - analysis; Fish Proteins - secretion; Follicle Stimulating Hormone - analysis; Follicle Stimulating Hormone - secretion; Fundamental and applied biological sciences. Psychology; Glycoproteins - analysis; Glycoproteins - secretion; Gonadotropins, Pituitary - secretion; Growth Hormone - analysis; Growth Hormone - secretion; Hormones and neuropeptides. Regulation; Hypothalamus - metabolism; Hypothalamus. Hypophysis. Epiphysis. Urophysis; Immunohistochemistry - methods; Luteinizing Hormone - analysis; Luteinizing Hormone - secretion; Male; Neuropeptides - pharmacology; Oncorhynchus nerka; Pituitary Gland - secretion; Pituitary Hormones - analysis; Pituitary Hormones - secretion; Prolactin - analysis; Prolactin - secretion; Regular papers; Reverse Transcriptase Polymerase Chain Reaction; Salmon - metabolism; Stimulation, Chemical; Vertebrates: endocrinology; Salmonidae; Oncorhynchus nerka; Somatotropin hormone; Gonadotropin; Gene expression; Neuropeptide; Hypothalamic hormone; Vertebrata; Adenohypophyseal hormone; Pisces; Adult animal; Pituitary gland; Localization
• ISSN: 0022-0795; 1479-6805
• DOI: 10.1677/joe.1.06494

We recently identified a cDNA encoding three novel fish hypothalamic neuropeptides, having LPXRF-NH2 from the goldfish brain. In this study, to clarify the physiological functions of these three LPXRFamide peptides (gfLPXRFa-1, -2, and -3), we analysed the localisation and hypophysiotrophic activity of these peptides using sockeye salmon, Oncorhynchus nerka, in which immunoassay systems for several anterior pituitary hormones have been developed. gfLPXRFa-immunoreactive cell bodies were detected in the nucleus posterioris periventricularis of the hypothalamus and immunoreactive fibres were distributed in various brain regions and the pituitary. We also detected gfLPXRFa-immunoreactivity in the pituitary by competitive enzyme-linked immunosorbent assay combined with reversed-phase HPLC. These three gfLPXRFamide peptides stimulated the release of FSH, LH and GH, but did not affect the release of prolactin (PRL) and somatolactin (SL) from cultured pituitary cells. These results suggest that novel fish hypothalamic LPXR-Famide peptides exist in the brain and pituitary of sockeye salmon and stimulate the release of gonadotrophins and GH from the pituitary.