title: Functional analysis of kisspeptin peptides in adult immature chub mackerel (Scomber japonicus) using an intracerebroventricular administration method.
abstract: In vertebrates (including teleosts), the pivotal hierarchical factor in the control of gonadotropin secretion is the hypothalamic gonadotropin-releasing hormone (GnRH) decapeptide, which regulates the release of pituitary follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Recently, kisspeptins encoded by the Kiss1 gene have been shown to act as upstream endogenous regulators of GnRH neurons in mammals. The chub mackerel (Scomber japonicus) brain expresses two kiss genes (kiss1 and kiss2) that show sexually dimorphic expression profiles during the seasonal gonadal cycle. In the present study, we evaluated the biological potency of kisspeptin peptides to induce transcriptional changes in gnrh1 (hypophysiotropic GnRH form in this species), fshβ and lhβ during the immature stage of adult chub mackerel (2+ years old). Synthetic Kiss1 pentadecapeptide (Kiss1-15) or Kiss2 dodecapeptide (Kiss2-12) at a dose of 100 ng were administered into the intracerebroventricular (ICV) region, and brains were sampled at 6 and 12 h post-injection. In female fish, gnrh1 levels decreased in the presence of both kisspeptin peptides at 12 h post-injection. No significant variation was observed in male fish. In contrast, ICV administration of Kiss2-12 (but not Kiss1-15) significantly increased fshβ and lhβ mRNAs at 12 h post-injection compared to a saline injected control in both sexes. These results suggested that synthetic Kiss2-12 could induce transcriptional changes in gnrh1 and gths.
authors.affiliation: Laboratory of Marine Biology, Faculty of Agriculture, Kyushu University, Fukuoka 812-8581 Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Ohga
authors.affiliation: Laboratory of Marine Biology, Faculty of Agriculture, Kyushu University, Fukuoka 812-8581 Japan.
authors.forename: Sethu
authors.initials: S
authors.lastname: Selvaraj
authors.affiliation: Laboratory of Marine Biology, Faculty of Agriculture, Kyushu University, Fukuoka 812-8581 Japan.
authors.forename: Hayato
authors.initials: H
authors.lastname: Adachi
authors.affiliation: Laboratory of Marine Biology, Faculty of Agriculture, Kyushu University, Fukuoka 812-8581 Japan.
authors.forename: Yui
authors.initials: Y
authors.lastname: Imanaga
authors.affiliation: Laboratory of Marine Biology, Faculty of Agriculture, Kyushu University, Fukuoka 812-8581 Japan.
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Nyuji
authors.affiliation: Laboratory of Marine Biology, Faculty of Agriculture, Kyushu University, Fukuoka 812-8581 Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Yamaguchi
authors.affiliation: Laboratory of Marine Biology, Faculty of Agriculture, Kyushu University, Fukuoka 812-8581 Japan. Electronic address: rinya_m@agr.kyushu-u.ac.jp.
authors.forename: Michiya
authors.initials: M
authors.lastname: Matsuyama
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D005260:Female; D005399:Fishes / Q000378:metabolism*; D037201:Follicle Stimulating Hormone, beta Subunit / Q000235:genetics / Q000378:metabolism; D007987:Gonadotropin-Releasing Hormone / Q000235:genetics / Q000378:metabolism; D007276:Injections, Intraventricular; D059648:Kisspeptins / Q000378:metabolism* / Q000494:pharmacology; D037101:Luteinizing Hormone, beta Subunit / Q000235:genetics / Q000378:metabolism; D008297:Male; D012333:RNA, Messenger / Q000378:metabolism; D012737:Sex Factors; D014158:Transcription, Genetic
chemical_list: D037201:Follicle Stimulating Hormone, beta Subunit; D059648:Kisspeptins; D037101:Luteinizing Hormone, beta Subunit; D012333:RNA, Messenger; D007987:Gonadotropin-Releasing Hormone
keywords: Kiss1-15; Kiss2-12; Perciformes