Estradiol regulation of uterine nucleolar estradiol binding sites

Biochim Biophys Acta. 1986 Feb 19;880(2-3):179-88. doi: 10.1016/0304-4165(86)90078-4.


Rat uterine nuclei contain two types of estrogen binding sites (I and II). Type I is the classical high-affinity, low-capacity binding component, while Type II has lower affinity and higher capacity. Investigation of the presence and number of estrogen-binding proteins in isolated uterine nucleoli, and the possible role of the estrogen-binding protein(s) in the stimulation of nucleolar RNA synthesis was undertaken. Isolated uterine nucleoli contain a large number of lower-affinity binding sites (Type II) but are devoid of a significant number of high-affinity binding protein(s) (Type I). Following in vivo treatment with estradiol the number of detectable Type II estradiol-binding sites in isolated uterine nucleoli increased with time of estrogen treatment, peaking between 16 and 24 h after hormone administration and gradually decreasing to control levels between 48 and 72 h. The estrogen-activated binding activity but not the basal activity is sensitive to dithiothreitol and insensitive to beta-mercaptoethanol during the in vitro assay, suggesting that important disulfide bonds may be involved in the estrogen-induced nucleolar binding sites. The in vivo activation of nucleolar estradiol-binding sites exhibits steroid specificity. Data indicate that a strong correlation exists between activation of uterine nucleolar transcriptional and estradiol-binding activities.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Cell Nucleolus / metabolism*
  • Disulfides / physiology
  • Dithiothreitol / pharmacology
  • Estradiol / pharmacology*
  • Female
  • In Vitro Techniques
  • Mercaptoethanol / pharmacology
  • RNA / biosynthesis
  • Rats
  • Receptors, Estradiol / drug effects
  • Receptors, Estradiol / metabolism*
  • Receptors, Estrogen / metabolism*
  • Transcription, Genetic
  • Uterus / metabolism*


  • Disulfides
  • Receptors, Estradiol
  • Receptors, Estrogen
  • Estradiol
  • Mercaptoethanol
  • RNA
  • Dithiothreitol