title: Two estrogen replacement therapies differentially regulate expression of estrogen receptors alpha and beta in the hippocampus and cortex of ovariectomized rat.
abstract: As estrogens have been implicated in altered cognitive function associated with menopause, the purpose of the present study was to determine the regulatory effects of different estrogen preparations on the expression of estrogen receptor subtypes in the hippocampus and cortex of ovariectomized rats. The expression of estrogen receptor mRNA and protein was determined with RT-PCR and immunohistochemistry, respectively. Two estrogen reagents, Premarin and Progynova, were used in the present study. Premarin, a conjugated equine estrogen, down-regulated ER alpha expression in the hippocampus and cortex of ovariectomized rats and had no effect on levels of ER beta expression in the same two regions. However, Progynova (valerate estradiol) was shown to up-regulate ER beta expression in the hippocampus and cortex and had no effect on the levels of ER alpha expression. Our present data suggest that different estrogen reagents used in estrogen replacement therapy could have different regulatory effects on the expression of estrogen receptor subtypes, which might, at least in part, explain why clinically, different estrogen preparations have distinct estrogenic effects on target organs.
authors.affiliation: Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, China.
authors.forename: Min
authors.initials: M
authors.lastname: Jin
authors.forename: Fan
authors.initials: F
authors.lastname: Jin
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.forename: Zhong
authors.initials: Z
authors.lastname: Chen
authors.forename: Hefeng
authors.initials: H
authors.lastname: Huang
mesh_terms: D000818:Animals; D015152:Blotting, Northern / Q000379:methods; D002452:Cell Count / Q000379:methods; D002540:Cerebral Cortex / Q000378:metabolism*; D004958:Estradiol / Q000031:analogs & derivatives / Q000097:blood / Q000494:pharmacology; D047628:Estrogen Receptor alpha / Q000235:genetics / Q000378:metabolism*; D047629:Estrogen Receptor beta / Q000235:genetics / Q000378:metabolism*; D015914:Estrogen Replacement Therapy / Q000379:methods*; D004966:Estrogens, Conjugated (USP) / Q000097:blood / Q000494:pharmacology; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects*; D006624:Hippocampus / Q000378:metabolism*; D007150:Immunohistochemistry / Q000379:methods; D010052:Ovariectomy / Q000379:methods; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods
chemical_list: D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D004966:Estrogens, Conjugated (USP); D012333:RNA, Messenger; D004958:Estradiol