title: Effects of steroids on endometrial oxytocin mRNA production.
abstract: In this study, the roles of oestrogen and progesterone in the regulation of oxytocin gene expression in equine endometrium were examined. Anoestrous mares (n=19) were assigned randomly to one of the following treatment groups: control (vehicle control for 1 day; n=3); progesterone (250 mg progesterone per day for 6 days; n=4); oestradiol (5 mg beta-oestradiol 17-valerate per day for 6 days; n=4); oestradiol plus short duration progesterone (5 mg beta-oestradiol 17-valerate per day for 6 days followed by 250 mg progesterone per day for 6 days; n=4); and oestradiol plus long duration progesterone (5 mg beta-oestradiol 17-valerate per day for 6 days followed by 250 mg progesterone per day for 12 days; n=4). Jugular venous blood samples were obtained for oestrogen and progesterone radioimmunoassays. Endometrial biopsies were obtained and total RNA was extracted. Expression of mRNA for oxytocin and glyceraldehyde 3'-phosphate dehydrogenase was assessed by RT-PCR and Southern blotting. Oxytocin mRNA abundance was significantly higher (P < 0.05) in the oestrogen-treated group than in all other groups. These data demonstrate that oestradiol priming for 6 days upregulated expression of the endometrial oxytocin gene. Progesterone treatment for either 6 or 12 days after oestradiol priming returned oxytocin mRNA abundance to levels similar to those of controls.
authors.affiliation: Department of Veterinary Science, Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546-0099, USA.
authors.forename: C Y
authors.initials: CY
authors.lastname: Behrendt-Adam
authors.forename: M H
authors.initials: MH
authors.lastname: Adams
authors.forename: K S
authors.initials: KS
authors.lastname: Simpson
authors.forename: K J
authors.initials: KJ
authors.lastname: McDowell
mesh_terms: D000818:Animals; D004334:Drug Administration Schedule; D004359:Drug Therapy, Combination; D004717:Endometrium / Q000187:drug effects / Q000378:metabolism*; D004958:Estradiol / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects*; D006736:Horses / Q000378:metabolism*; D010121:Oxytocin / Q000235:genetics / Q000378:metabolism*; D011374:Progesterone / Q000008:administration & dosage / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D011374:Progesterone; D004958:Estradiol; D010121:Oxytocin