Novel fish hypothalamic neuropeptides stimulate the release of gonadotrophins and growth hormone from the pituitary of sockeye salmon.
We recently identified a cDNA encoding three novel fish hypothalamic neuropeptides, having LPXRF-NH(2) 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.
Amano
Masafumi
M
School of Fisheries Sciences, Kitasato University, Ofunato, Iwate 022-0101, Japan.
Moriyama
Shunsuke
S
Iigo
Masayuki
M
Kitamura
Shoji
S
Amiya
Noriko
N
Yamamori
Kunio
K
Ukena
Kazuyoshi
K
Tsutsui
Kazuyoshi
K
D000818:Animals; D002478:Cells, Cultured; D029941:Fish Proteins / Q000032:analysis / Q000378:metabolism; D005640:Follicle Stimulating Hormone / Q000032:analysis / Q000378:metabolism; D006023:Glycoproteins / Q000032:analysis / Q000378:metabolism; D006065:Gonadotropins, Pituitary / Q000378:metabolism*; D013006:Growth Hormone / Q000032:analysis / Q000378:metabolism*; D007031:Hypothalamus / Q000378:metabolism*; D007150:Immunohistochemistry / Q000379:methods; D007986:Luteinizing Hormone / Q000032:analysis / Q000378:metabolism; D008297:Male; D009479:Neuropeptides / Q000494:pharmacology*; D010902:Pituitary Gland / Q000378:metabolism*; D010907:Pituitary Hormones / Q000032:analysis / Q000378:metabolism; D011388:Prolactin / Q000032:analysis / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012474:Salmon / Q000378:metabolism*; D013268:Stimulation, Chemical
D029941:Fish Proteins; D006023:Glycoproteins; D006065:Gonadotropins, Pituitary; D009479:Neuropeptides; D010907:Pituitary Hormones; C064448:somatolactin protein, fish; D011388:Prolactin; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D013006:Growth Hormone