title: Effects of hormonally active agents on steroid hormone receptor expression and cell proliferation in the myometrium of ovariectomized macaques.
abstract: Hormone replacement therapy and selective estrogen receptor modulators have been controversial treatment options for postmenopausal women because of their potential health benefits and/or risks. In this study, we determine the effects of the hormonally active compounds, conjugated equine estrogens (CEE), medroxyprogesterone acetate (MPA), CEE + MPA, and tamoxifen (TAM) on the myometrium of ovariectomized macaques. Immunoexpression of estrogen receptor-α (ERα), progesterone receptor (PR), and Ki-67 in the myometrium is assessed. We found no significant difference in ERα myometrial expression in the CEE, MPA, and CEE + MPA treatment groups, but there was a significant decrease in expression in animals administered TAM versus controls. Conjugated equine estrogen-, TAM-, and CEE + MPA-treated animals had significantly increased expression of PR in myometrial cells and there was no difference in PR expression in cells from MPA-treated animals versus control animals. Myometrial cell proliferation did not significantly differ between the controls and any of the treatment groups, although normalized Ki-67 values were somewhat higher in the CEE and TAM groups. These data suggest that ERα and PR expression in the myometrium is influenced by treatment with hormonally active agents.
authors.affiliation: Integrated Laboratory Systems (ILS), Research Triangle Park, North Carolina, USA.
authors.forename: Georgette D
authors.initials: GD
authors.lastname: Hill
authors.forename: Alicia B
authors.initials: AB
authors.lastname: Moore
authors.forename: Grace E
authors.initials: GE
authors.lastname: Kissling
authors.forename: Norris D
authors.initials: ND
authors.lastname: Flagler
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Ney
authors.forename: J Mark
authors.initials: JM
authors.lastname: Cline
authors.forename: Darlene
authors.initials: D
authors.lastname: Dixon
mesh_terms: D000818:Animals; D049109:Cell Proliferation; D047628:Estrogen Receptor alpha / Q000378:metabolism; D004966:Estrogens, Conjugated (USP) / Q000494:pharmacology*; D005260:Female; D020249:Hormone Replacement Therapy / Q000379:methods; D019394:Ki-67 Antigen / Q000378:metabolism; D008252:Macaca fascicularis; D017258:Medroxyprogesterone Acetate / Q000494:pharmacology*; D009215:Myometrium / Q000187:drug effects* / Q000378:metabolism; D010052:Ovariectomy; D011980:Receptors, Progesterone / Q000187:drug effects*; D020845:Selective Estrogen Receptor Modulators / Q000494:pharmacology; D013629:Tamoxifen / Q000494:pharmacology*
chemical_list: D047628:Estrogen Receptor alpha; D004966:Estrogens, Conjugated (USP); D019394:Ki-67 Antigen; D011980:Receptors, Progesterone; D020845:Selective Estrogen Receptor Modulators; D013629:Tamoxifen; D017258:Medroxyprogesterone Acetate