title: Neuroanatomical investigation of the gonadotrophin-releasing hormone 1 system in the seasonally breeding Cape dune mole-rat, Bathyergus suillus.
abstract: The gonadotrophin-releasing hormone 1 (GnRH1) system has been investigated immunohistochemically in Cape dune mole-rats (Bathyergus suillus), subterranean rodents that normally display severe aggression towards conspecifics. These animals breed seasonally and show a reduced mean plasma level of luteinising hormone during the non-breeding season. GnRH1-immunoreactive (ir) cell bodies and processes are found in the septal/preoptic area and the mediobasal hypothalamus; the cell bodies are found in equal measure in these two regions. Dense aggregations of GnRH1-ir fibres are present in the organum vasculosum of the lamina terminalis and the external zone of the median eminence. The total number of detectable GnRH1-ir cell bodies does not differ between the sexes or within the sexes between breeding and non-breeding seasons. Similarly there is no difference in the distribution of detectable GnRH1-ir cell bodies in male and female mole-rats in and out of the breeding season. Although the average size of GnRH1-ir cell bodies does not differ between the seasons in males, their size in females is significantly smaller in the non-breeding season. Whether this reduced size reflects reduced GnRH1 synthesis remains to be determined.
authors.affiliation: Mammal Research Institute, Department of Zoology & Entomology, University of Pretoria, Pretoria 0002, South Africa. lhart@deat.gov.za
authors.forename: Leanne
authors.initials: L
authors.lastname: Hart
authors.forename: Nigel C
authors.initials: NC
authors.lastname: Bennett
authors.forename: Theodosis
authors.initials: T
authors.lastname: Kalamatianos
authors.forename: Maria K
authors.initials: MK
authors.lastname: Oosthuizen
authors.forename: Jennifer U M
authors.initials: JU
authors.lastname: Jarvis
authors.forename: M Justin
authors.initials: MJ
authors.lastname: O'Riain
authors.forename: Clive W
authors.initials: CW
authors.lastname: Coen
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001921:Brain / Q000033:anatomy & histology* / Q000166:cytology / Q000378:metabolism*; D002452:Cell Count; D048429:Cell Size; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D007031:Hypothalamus / Q000033:anatomy & histology / Q000166:cytology / Q000378:metabolism; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D008473:Median Eminence / Q000033:anatomy & histology / Q000166:cytology / Q000378:metabolism; D010784:Photomicrography; D011301:Preoptic Area / Q000033:anatomy & histology / Q000166:cytology / Q000378:metabolism; D012377:Rodentia / Q000033:anatomy & histology* / Q000378:metabolism*; D012621:Seasons; D020665:Septum of Brain / Q000033:anatomy & histology / Q000166:cytology / Q000378:metabolism; D012727:Sex Characteristics; D012726:Sexual Behavior, Animal / Q000502:physiology
chemical_list: D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone