title: Immunocytochemical localization of kisspeptin neurons in the rat forebrain with special reference to sexual dimorphism and interaction with GnRH neurons.
abstract: Kisspeptin/metastin has been implicated as a critical regulator in luteinizing hormone (LH) secretion and the reproductive system mediating the effect of estrogen on GnRH neurons.  In the present study we examined the sex differences in the effects of estrogen on Kiss1/kisspeptin expression in the forebrain by using gonadectomized rats to assess the interaction of kisspeptin and GnRH neurons.  Kiss1/kisspeptin cell bodies were abundant in the rostral periventricular area of the third ventricle (RV3P) and the arcuate nucleus (ARC).  A few cell bodies were also observed in other portions of the forebrain, i.e. the bed nucleus of the stria terminalis (BST), the paraventricular hypothalamic nucleus (PaAP), the ventromedial hypothalamic nucleus (VMH), and the medial amygdaloid nucleus (MeA).  Kisspeptin-immunoreactive fibers were found mainly in the median eminence (ME), the ARC, and the RV3P, but were scarce in the preoptic area (POA), where GnRH neurons are localized.  We also found that estrogen triggers expression of the Kiss1 gene and peptide within all the regions except the ARC, and that the effects in the RV3P, BST, PaAP, and VMH are greater in estrogen treated ovariectomized female rat.  It is noteworthy that kisspeptin and GnRH neurons were densely associated in the ME but were rarely in contact in the POA.  Thus, our results suggest that kisspeptin-positive neurons, except for the ones in the ARC, are related not only to estrogen-positive feedback, but also sex dimorphism, and that kisspeptin regulates GnRH release in the ME rather than the POA.
authors.affiliation: Graduate School of Science and Engineering, Saitama University, Saitama, Japan.
authors.forename: Zhifang
authors.initials: Z
authors.lastname: Xu
authors.forename: Shigehito
authors.initials: S
authors.lastname: Kaga
authors.forename: Akikazu
authors.initials: A
authors.lastname: Mochiduki
authors.forename: Jun
authors.initials: J
authors.lastname: Tsubomizu
authors.forename: Sachika
authors.initials: S
authors.lastname: Adachi
authors.forename: Takafumi
authors.initials: T
authors.lastname: Sakai
authors.forename: Kinji
authors.initials: K
authors.lastname: Inoue
authors.forename: Akihito A
authors.initials: AA
authors.lastname: Adachi
mesh_terms: D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000166:cytology / Q000378:metabolism; D004958:Estradiol / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D007150:Immunohistochemistry; D059648:Kisspeptins / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008473:Median Eminence / Q000166:cytology / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D009919:Orchiectomy; D009928:Organ Specificity; D010052:Ovariectomy; D016548:Prosencephalon / Q000166:cytology / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012727:Sex Characteristics; D020542:Third Ventricle / Q000166:cytology / Q000378:metabolism
chemical_list: C491406:Kiss1 protein, rat; D059648:Kisspeptins; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D007987:Gonadotropin-Releasing Hormone; D004958:Estradiol