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Endometrial effects of selective estrogen receptor modulators (SERMs) on estradiol-responsive gene expression are

Yuhua Z Farnell1, Nancy H Ing

  • 1Department of Animal Science, Faculties of Genetics and Reproductive Biology, Texas A&M University, College Station, TX 77843-2471, USA.

The Journal of Steroid Biochemistry and Molecular Biology
|May 28, 2003
PubMed

Insights

Three selective estrogen receptor modulators (SERMs) were tested for their effects on sheep endometrial gene expression. EM-800 and GW 5638 showed fewer estrogenic effects than 4-OH-tamoxifen, with EM-800 being the most potent antagonist.

Area of Science:

  • Reproductive Endocrinology
  • Molecular Biology
  • Pharmacology

Background:

  • Selective estrogen receptor modulators (SERMs) are crucial in managing hormone-dependent conditions.
  • Understanding SERM interactions with estrogen receptors (ER) in the endometrium is vital for therapeutic development.

Purpose of the Study:

  • To investigate the inhibitory effects of three SERMs (4-OH-tamoxifen, EM-800, and GW 5638) on estradiol-responsive gene expression in sheep endometrium.
  • To compare the agonist and antagonist properties of these SERMs in a relevant in vivo model.

Main Methods:

  • Uteri from ovariectomized ewes were infused with SERMs and/or 17beta-estradiol (E2).
  • Gene expression analysis was performed using Northern blot and in situ hybridization.
  • Protein levels were assessed via immunohistochemistry.

Main Results:

  • E2 treatment increased ER, PR, GAPDH, and CYC mRNA levels.
  • 4-OH-tamoxifen and GW 5638 increased ER gene expression but antagonized E2-induced PR and CYC.
  • EM-800 acted as an E2-agonist for GAPDH but antagonized E2-induced ER, PR, and CYC, also decreasing ER protein levels.

Conclusions:

  • GW 5638 and EM-800 exhibit fewer agonist effects on endometrial gene expression compared to 4-OH-tamoxifen.
  • EM-800 demonstrates significant antagonism of E2-enhanced ER, PR, and CYC levels, likely by inhibiting ER gene expression at both mRNA and protein levels.

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