title: Oestrogen and progesterone receptor gene expression in canine oocytes and cumulus cells throughout the oestrous cycle.
abstract: The aim of this research was to analyze oestrogen receptor-alpha (ERalpha), ERbeta and progesterone receptor (PR) gene expression in the canine oocyte and cumulus cells throughout the oestrous cycle. Ovaries from 38 bitches were recovered after ovariohysterectomy and sliced. The phase of the oestrous cycle was determined by vaginal cytology, vaginoscopy and serum hormonal measurements. Oocytes were mechanically denuded by repeated pipetting. For each phase of the cycle, a sample was composed by a pool of 50 oocytes (sample number: prooestrus = 3, oestrus = 8, dioestrus = 5 and anoestrus = 5) or a pool of cumulus cells (prooestrus = 4, oestrus = 7, dioestrus = 4 and anoestrus = 6). Oocyte and cumulus cells' total RNA was isolated and reverse transcription was conducted to perform real-time PCR. Oestrogen receptor-alpha was expressed throughout the cycle in the oocyte (33.33%, 25.0%, 20.0% and 60.0% for prooestrus, oestrus, dioestrus and anoestrus, respectively) and cumulus cells (50.0%, 47.14%, 25.0% and 66.67% for prooestrus, oestrus, dioestrus and anoestrus, respectively). In the oocyte, the ERbeta was also expressed in all phases of the cycle (33.33%, 50.0%, 20.0% and 60.0% for prooestrus, oestrus, dioestrus and anoestrus, respectively), whereas in cumulus cells, ERbeta was only expressed during prooestrus (50%) and oestrus (14.29%). Interestingly, while the oocyte PR was not detected in any phase of the cycle, this receptor was expressed during prooestrus (50%), oestrus (42.86%) and anoestrus (16.67%) in cumulus cells. In conclusion, canine oocytes express ERalpha and ERbeta throughout the oestrous cycle, however, there is a lack of PR expression in all these phases. Moreover, in cumulus cells, only ERalpha was expressed throughout the oestrous cycle.
authors.affiliation: Laboratory of In Vitro Fertilization, Cloning and Animal Transgenesis, Department of Animal Reproduction, School of Veterinary Medicine and Animal Sciences, University of Sao Paulo, Sao Paulo, Brazil. ffpaulalopes@yahoo.com
authors.forename: J S A
authors.initials: JS
authors.lastname: Gonçalves
authors.forename: C I
authors.initials: CI
authors.lastname: Vannucchi
authors.forename: F C
authors.initials: FC
authors.lastname: Braga
authors.forename: F F
authors.initials: FF
authors.lastname: Paula-Lopes
authors.forename: M P
authors.initials: MP
authors.lastname: Milazzotto
authors.forename: M E O A
authors.initials: ME
authors.lastname: Assumpção
authors.forename: J A
authors.initials: JA
authors.lastname: Visintin
mesh_terms: D000818:Animals; D054885:Cumulus Cells / Q000378:metabolism*; D004285:Dogs / Q000502:physiology*; D030762:Estrous Cycle / Q000502:physiology*; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology; D009865:Oocytes / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000378:metabolism*
chemical_list: D011960:Receptors, Estrogen; D011980:Receptors, Progesterone