title: Antiestrogenic effect of opioid peptides in rat uterus.
abstract: The effects of a single injection or continuous infusion of opioid peptide, [D-Met(2),pro(5)]enkephalinamide (ENK) on the hormone binding and transcriptional properties of estrogen receptors were investigated in estradiol (E(2)) treated rat uterus. The level of estrogen- (ER) and progesterone receptor (PR) proteins, the hormone binding of E(2) receptors and the effects of single injection of ENK with or without naltrexone (NAL) on the E(2)-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 E(2) binding turned into positive cooperativity. The E(2)-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 E(2) in the gene regulation of rat uterus.
authors.affiliation: Medical Faculty, Institute of Physiology, University of Pécs, Szigeti str.12, H-7643, Pécs, Hungary. oszter@physiol.pote.hu
authors.forename: A
authors.initials: A
authors.lastname: Oszter
authors.forename: Z
authors.initials: Z
authors.lastname: Vértes
authors.forename: B
authors.initials: B
authors.lastname: Töröcsik
authors.forename: J L
authors.initials: JL
authors.lastname: Környei
authors.forename: K A
authors.initials: KA
authors.lastname: Kovács
authors.forename: M
authors.initials: M
authors.lastname: Vértes
mesh_terms: D000818:Animals; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004744:Enkephalin, Methionine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology*; D004958:Estradiol / Q000378:metabolism / Q000494:pharmacology; D020847:Estrogen Receptor Modulators / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D018847:Opioid Peptides / Q000008:administration & dosage / Q000819:agonists / Q000494:pharmacology*; D010052:Ovariectomy; D011485:Protein Binding / Q000187:drug effects; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014599:Uterus / Q000187:drug effects* / Q000378:metabolism
chemical_list: D020847:Estrogen Receptor Modulators; D018847:Opioid Peptides; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D018808:Transcription Factor AP-1; D004958:Estradiol; D004744:Enkephalin, Methionine; C021717:enkephalin, Met(2)-ProNH2(5)-; D004247:DNA