Role of endogenous opioids in progesterone antagonism on oestradiol-induced DNA synthesis in the rat uterus

Tamás Ördög, Zsuzsanna Vértes, Marietta Vértes

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To probe the possible involvement of endogenous opioid peptides (EOPs) in progesterone (PG) antagonism on oestradiol-17β-(OE) induced uterine cell proliferation, the opioid antagonist naltrexone hydrochloride (NTC) and anti-[Met5]-enkephalin antiserum (AME) were investigated for their effect on uterine DNA synthesis in ovariectomized rats pretreated with OE and PG 24 h before killing. An an index of DNA synthesis the rat of vitro incorporation of [3H]thymidine ([3H]TdR) into DNA was measured. The inhibitory effect of PG on OE-induced DNA synthesis could be diminished by ∼ 42 and ∼ 20% by the NTX treatments given directly into the uterine horns 13 and 4 h before killing, respectively. Intraluminal AME treatments were only effective when they were administered 13 h before decapitation. Systemic blockade of opioid receptors by intraperitoneal NTX injections given every 6 h to the OE + PG-treated rats did not result in the disinhibition of uterine [3H]TdR incorporation. Our results suggest the involvement of EOPs-including [Met5]-enkephalin-as autocrine/paracrine factors in the PG antagonism on OE-induced uterine DNA synthesis.

Original languageEnglish (US)
Pages (from-to)455-457
Number of pages3
JournalJournal of Steroid Biochemistry and Molecular Biology
Issue number5
StatePublished - May 1993


ASJC Scopus subject areas

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

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