title: Peripheral kisspeptin reverses short photoperiod-induced gonadal regression in Syrian hamsters by promoting GNRH release.
abstract: In seasonal breeders, reproduction is synchronised by day length via the pineal hormone melatonin. In short winter days (short day, SD), the Syrian hamster displays a complete gonadal atrophy together with a marked reduction in expression of kisspeptins (Kp), a family of potent hypothalamic stimulators of GNRH neurons. Both central and peripheral acute injections of Kp have been reported to activate the gonadotropic axis in mammals. The aim of this study was to determine if and how peripheral administration of Kp54 could restore gonadal function in photo-inhibited hamsters. Testicular activity of hamsters kept in SD was reactivated by two daily i.p. injections of Kp54 but not by chronic subcutaneous delivery of the same peptide via mini-pumps. Acute i.p. injection of Kp54-induced FOS (c-Fos) expression in a large number of GNRH neurons and pituitary gonadotrophs together with a strong increase in circulating testosterone. The activation of pituitary cells by Kp was inhibited by preadministration of the GNRH receptor antagonist acyline. Altogether, our results demonstrate that peripheral Kp54 activates the gonadotropic axis by stimulating GNRH release and indicate that an appropriate protocol of long-term systemic Kp administration can recrudesce a photo-inhibited reproductive axis.
authors.affiliation: Département de Neurobiologie des Rythmes, Institut des Neurosciences Cellulaires et Intégratives (INCI), CNRS UPR 3212, Université de Strasbourg, 5 rue Blaise Pascal, 67084 cedex Strasbourg, France.
authors.forename: L
authors.initials: L
authors.lastname: Ansel
authors.forename: A H
authors.initials: AH
authors.lastname: Bentsen
authors.forename: C
authors.initials: C
authors.lastname: Ancel
authors.forename: M
authors.initials: M
authors.lastname: Bolborea
authors.forename: P
authors.initials: P
authors.lastname: Klosen
authors.forename: J D
authors.initials: JD
authors.lastname: Mikkelsen
authors.forename: V
authors.initials: V
authors.lastname: Simonneaux
mesh_terms: D000279:Administration, Cutaneous; D000818:Animals; D001284:Atrophy / Q000139:chemically induced; D006224:Cricetinae; D019610:Cytoprotection / Q000187:drug effects; D004353:Drug Evaluation, Preclinical; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D006066:Gonads / Q000187:drug effects* / Q000473:pathology; D006801:Humans; D059648:Kisspeptins / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D008647:Mesocricetus; D017440:Photoperiod; D013737:Testis / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D013997:Time Factors; D015854:Up-Regulation
chemical_list: C106628:KISS1 protein, human; D059648:Kisspeptins; D007987:Gonadotropin-Releasing Hormone