title: Ovarian suppression in a marsupial following single treatment with a gonadotrophin-releasing hormone agonist in microspheres.
abstract: The effect of treatment with Lucrin Depot (1 month), a microsphere gonadotrophin-releasing hormone agonist preparation, was investigated in the fat-tailed dunnart (Sminthopsis crassicaudata) as a potential strategy to synchronise cycling. The status of the ovaries (ovarian size, number and size of Graafian follicles and corpora lutea) and reproductive tract (weight, vascularity and muscularity) in twelve untreated females were assessed to establish the activity parameters for randomly selected cycling animals. Thirty-six females were treated with 1mgkg-1(n=12), 10mgkg-1(n=12) or 20mgkg-1(n=12) Lucrin Depot. At 4, 6 and 8 weeks the reproductive tracts were assessed using the criteria developed in the untreated females. All of the females treated with 10mgkg-1showed suppression at 4 weeks and 25% showed return of reproductive activity at 8 weeks. A dose of 1mgkg-1did not appear to suppress reproductive activity and 20mgkg-1gave equivocal results, with evidence of both suppression and activity. The results indicate that Lucrin Depot appears to be a promising agent to regulate and potentially synchronise breeding activity in the fat-tailed dunnart.
authors.affiliation: School of Environmental and Life Sciences, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia.
authors.forename: Ryan Robert
authors.initials: RR
authors.lastname: Witt
authors.affiliation: School of Environmental and Life Sciences, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia.
authors.forename: Ian Ross
authors.initials: IR
authors.lastname: Forbes
authors.affiliation: Melbourne IVF, 344 Victoria Parade, East Melbourne, Vic. 3002, Australia.
authors.forename: John
authors.initials: J
authors.lastname: McBain
authors.affiliation: School of Environmental and Life Sciences, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia.
authors.forename: John Cameron
authors.initials: JC
authors.lastname: Rodger
mesh_terms: D000818:Animals; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000819:agonists*; D008394:Marsupialia; D008863:Microspheres; D010053:Ovary / Q000187:drug effects*
chemical_list: D007987:Gonadotropin-Releasing Hormone