title: The effects of gonadal steroid manipulation on the expression of Kiss1 mRNA in rat arcuate nucleus during postnatal development.
abstract: Kisspeptins, encoded by Kiss1 gene, play pivotal roles in the regulation of reproduction. Recently, several studies reported a sex difference in Kiss1 expression in the arcuate nucleus (ARC) during the neonatal period. In this study, we investigated the effect of gonadal steroid manipulation on the sex difference in Kiss1 expression in ARC of rats. At neonatal and prepubertal stages, females had a greater number of Kiss1 neurons than the males. Gonadectomy at those stages resulted in significant increases in the Kiss1 neuron number and the sex differences disappeared. We also confirmed the expression of estrogen receptor α in kisspeptin neurons in neonates. Altogether, our results indicate that ARC Kiss1 expression is negatively regulated by gonadal steroids from early postnatal stages, and that the sex difference in ARC Kiss1 expression is attributed to the difference in circulating gonadal steroid levels. We also found that neonatal estrogenization inhibits Kiss1 expression and impairs negative feedback system.
authors.affiliation: Department of Anatomy and Neurobiology, Graduate School of Medicine, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo, 113-8602, Japan. takumiken@nms.ac.jp
authors.forename: Ken
authors.initials: K
authors.lastname: Takumi
authors.forename: Norio
authors.initials: N
authors.lastname: Iijima
authors.forename: Kinuyo
authors.initials: K
authors.lastname: Iwata
authors.forename: Shimpei
authors.initials: S
authors.lastname: Higo
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Ozawa
mesh_terms: D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000378:metabolism / Q000502:physiology*; D047628:Estrogen Receptor alpha / Q000378:metabolism; D005260:Female; D012739:Gonadal Steroid Hormones / Q000378:metabolism*; D059648:Kisspeptins / Q000096:biosynthesis* / Q000235:genetics*; D008297:Male; D009474:Neurons / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics*; D051381:Rats; D017208:Rats, Wistar; D012098:Reproduction; D012727:Sex Characteristics
chemical_list: D047628:Estrogen Receptor alpha; D012739:Gonadal Steroid Hormones; C491406:Kiss1 protein, rat; D059648:Kisspeptins; D012333:RNA, Messenger