title: Central distribution of kiss2 neurons and peri-pubertal changes in their expression in the brain of male and female red seabream Pagrus major.
abstract: kisspeptins that are encoded by kiss1 gene are now considered the key regulator of reproduction from a number of studies in mammals. In most vertebrates, a paralogue of kiss1, called kiss2, is also present, and the functional significance of kisspeptins is not known precisely. In the present study, we have cloned kiss2 from a perciform teleost, the red seabream Pagrus major. The amino acid sequence deduced from the red seabream kiss2 contained a highly conserved 10-amino-acid residue, Kiss2(10) or kp-10. A kiss1-like transcript was also identified, but it appears to be non-functional due to the presence of a "premature" stop codon. Neurons that express kiss2 mRNA were distributed in the dorsal (NRLd) and ventral (NRLv) parts of nucleus recessi lateralis in the hypothalamus. In some fish a few kiss2-expressing neurons were detected in the preoptic area and nucleus ventralis tuberis. The number of kiss2-expressing neurons in the NRLd was larger during the first spawning season in both males and females compared with fish in the post-spawning periods. In males the number of kiss2 neurons in the NRLd of maturing fish was also larger than those in the post-spawning periods. In males the number of kiss2 neurons in the NRLv showed a similar pattern of changes to that of NRLd, while significant changes were not detected for females. The numbers of gonadotropin-releasing hormone 1 (GnRH1)-immunoreactive neurons in the preoptic area showed a similar pattern of change as those of kiss2 cells of the NRLd in both males and females (and also the NRLv in males). These results are in good agreement with the hypothesis that kiss2 neurons are involved in pubertal processes via regulatory influences on GnRH1 neurons in red seabream.
authors.affiliation: Laboratory of Fish Biology, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Shimizu
authors.forename: Junko
authors.initials: J
authors.lastname: Tomikawa
authors.forename: Keisuke
authors.initials: K
authors.lastname: Hirano
authors.forename: Yoko
authors.initials: Y
authors.lastname: Nanikawa
authors.forename: Yasuhisa
authors.initials: Y
authors.lastname: Akazome
authors.forename: Shinji
authors.initials: S
authors.lastname: Kanda
authors.forename: Yukinori
authors.initials: Y
authors.lastname: Kazeto
authors.forename: Koichi
authors.initials: K
authors.lastname: Okuzawa
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Uenoyama
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ohkura
authors.forename: Hiroko
authors.initials: H
authors.lastname: Tsukamura
authors.forename: Kei-ichiro
authors.initials: K
authors.lastname: Maeda
authors.forename: Koichiro
authors.initials: K
authors.lastname: Gen
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Oka
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Yamamoto
mesh_terms: D000375:Aging / Q000502:physiology; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000166:cytology / Q000502:physiology*; D002452:Cell Count; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D007987:Gonadotropin-Releasing Hormone / Q000502:physiology; D007031:Hypothalamus / Q000502:physiology; D059648:Kisspeptins / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D008297:Male; D008969:Molecular Sequence Data; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D011301:Preoptic Area / Q000502:physiology; D021541:Sea Bream / Q000502:physiology*; D012741:Sexual Maturation / Q000502:physiology*
chemical_list: D059648:Kisspeptins; D007987:Gonadotropin-Releasing Hormone