title: LPXRFamide peptide stimulates growth hormone and prolactin gene expression during the spawning period in the grass puffer, a semi-lunar synchronized spawner.
abstract: Gonadotropin-inhibitory hormone (GnIH) plays as a multifunctional neurohormone that controls reproduction in birds and mammals. LPXRFamide (LPXRFa) peptide, the fish ortholog of GnIH, has been shown to regulate the secretion of not only gonadotropin (GTH) but also growth hormone (GH) and prolactin (PRL), which are potentially important for gonadal function. To investigate the role of LPXRFa peptide on reproduction of the grass puffer, which spawns in semilunar cycles, we examined changes in the levels of gh and prl expression over the several months during the reproductive cycle, and the effects of goldfish LPXRFa peptide-1 (gfLPXRFa-1) on their expression were examined using primary pituitary cultures. The expression levels of both gh and prl showed significant changes during the reproductive cycle in both sexes with one peak in the spawning and pre-spawning periods for gh and prl, respectively. Particularly, gh showed substantial increase in expression in the spawning and post-spawning periods, indicative of its essentiality in the advanced stage of reproduction. gfLPXRFa-1 stimulated the expression of both gh and prl but there was a marked difference in response between them: gfLPXRFa-1 stimulated gh expression at a relatively low dose but little effect was observed on prl. Combined with the previous results of daily and circadian oscillations of lpxrfa expression, the present results suggest that LPXRFa peptide is important in the control of the cyclic reproduction by serving as a multifunctional hypophysiotropic factor that regulates the expression of gh and prl as well as GTH subunit genes.
authors.affiliation: Sado Marine Biological Station, Faculty of Science, Niigata University, Sado, Niigata 952-2135, Japan.
authors.forename: Md
authors.initials: M
authors.lastname: Shahjahan
authors.affiliation: Shimonoseki Marine Science Museum "Kaikyokan", Shimonoseki Academy of Marine Science, Yamaguchi 750-0036, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Doi
authors.affiliation: Sado Marine Biological Station, Faculty of Science, Niigata University, Sado, Niigata 952-2135, Japan. Electronic address: hando311@cc.niigata-u.ac.jp.
authors.forename: Hironori
authors.initials: H
authors.lastname: Ando
mesh_terms: D000818:Animals; D005260:Female; D015870:Gene Expression / Q000187:drug effects*; D013006:Growth Hormone / Q000235:genetics* / Q000378:metabolism; D008297:Male; D009479:Neuropeptides / Q000494:pharmacology*; D010902:Pituitary Gland / Q000187:drug effects* / Q000378:metabolism; D011388:Prolactin / Q000235:genetics* / Q000378:metabolism; D012098:Reproduction / Q000187:drug effects / Q000502:physiology; D023721:Tetraodontiformes / Q000235:genetics
chemical_list: D009479:Neuropeptides; C416987:RFamide peptide; D011388:Prolactin; D013006:Growth Hormone
keywords: GnIH; Growth hormone; LPXRFamide peptide; Lunar cycle; Prolactin; Puffer fish; Seasonal reproduction