Characterization of the biological roles of the estrogen receptors, ERalpha and ERbeta, in estrogen target tissues in vivo through the use of an ERalpha-selective ligand

Endocrinology. 2002 Nov;143(11):4172-7. doi: 10.1210/en.2002-220403.


Estrogens elicit many biomedically important responses in different target tissues, and the respective roles of the two estrogen receptors, ERalpha and ERbeta, in mediating these bioactivities is incompletely understood. In this study, we investigated the activity of an ERalpha-selective agonist ligand, propyl pyrazole triol (PPT), in several rat animal models to define the involvement of ERalpha in these biological responses. In a short-term (4 d) uterotrophic assay, PPT was found to be as efficacious as 17alpha-ethinyl-17beta-estradiol in stimulating uterine weight gain and up-regulating complement 3 gene expression. In a 6-wk chronic model, PPT completely prevented the ovariectomy-induced body weight increase and loss of bone mineral density. It also increased uterine weight and markedly reduced plasma cholesterol levels in these mature animals. PPT was also effective in the brain. It increased progesterone receptor mRNA in the arcuate and ventromedial nuclei of the hypothalamus and prevented experimentally induced hot flushes. Our findings indicate that several physiologically relevant estrogen-induced tissue responses can be effectively evoked via ERalpha alone. By providing an approach that is complementary to that of analyzing the phenotype and response of ER knockout animals, our findings also demonstrate that ER subtype-selective ligands can play a valuable role in enhancing our understanding of how estrogens work through the two ER subtypes.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Body Weight / drug effects
  • Bone Density / drug effects
  • Complement C3 / genetics
  • Estrogen Receptor alpha
  • Estrogen Receptor beta
  • Estrogens / pharmacology*
  • Ethinyl Estradiol / pharmacology
  • Female
  • Gene Expression / drug effects
  • Hypothalamus / drug effects
  • Hypothalamus / metabolism
  • Ligands
  • Organ Size / drug effects
  • Ovariectomy
  • Phenols
  • Pyrazoles / metabolism
  • Pyrazoles / pharmacology*
  • RNA, Messenger / analysis
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Estrogen / physiology*
  • Receptors, Progesterone / genetics
  • Skin Temperature / drug effects
  • Uterus / drug effects*


  • Complement C3
  • Estrogen Receptor alpha
  • Estrogen Receptor beta
  • Estrogens
  • Ligands
  • Phenols
  • Pyrazoles
  • RNA, Messenger
  • Receptors, Estrogen
  • Receptors, Progesterone
  • 4,4',4''-(4-propyl-((1)H)-pyrazole-1,3,5-triyl) tris-phenol
  • Ethinyl Estradiol