Antiestrogenic effect of opioid peptides in rat uterus

Angéla Oszter, Zsuzsanna Vértes, Beáta Töröcsik, József L. Környei, Kálmán A. Kovács, Marietta Vértes

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The effects of a single injection or continuous infusion of opioid peptide, [D-Met2,pro5]enkephalinamide (ENK) on the hormone binding and transcriptional properties of estrogen receptors were investigated in estradiol (E2) treated rat uterus. The level of estrogen- (ER) and progesterone receptor (PR) proteins, the hormone binding of E2 receptors and the effects of single injection of ENK with or without naltrexone (NAL) on the E2-induced changes in the level of Fos and Jun proteins and the binding of AP-1 proteins to DNA were studied. The receptor proteins levels were determined by Western blots and the binding of AP-1 to DNA by electrophoretic mobility shift assay. Both the ER and PR protein concentrations and the [3H]Estradiol binding to the high affinity nuclear receptors decreased after ENK treatment during the first two days. At 72 h the PR concentration decreased further, while no significant changes were found in the level of ER, however, at this time the former competitive E2 binding turned into positive cooperativity. The E2-induced increase in the level of Fos proteins and the binding of AP-1 proteins to DNA was inhibited by a single injection of ENK. We conclude that the endogenous opioid peptides may interact with E2 in the gene regulation of rat uterus. Copyright (C) 2000 Elsevier Science Ltd.

Original languageEnglish
Pages (from-to)25-32
Number of pages8
JournalJournal of Steroid Biochemistry and Molecular Biology
Issue number1-2
Publication statusPublished - Nov 8 2000



  • AP-1 complex
  • Estrogen binding
  • Estrogen receptor
  • Opioid peptides
  • Rat uterus

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Biochemistry
  • Molecular Medicine
  • Molecular Biology
  • Endocrinology
  • Clinical Biochemistry
  • Cell Biology

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