Gonadal steroid hormones upregulate medial preoptic μ-opioid receptors in the rat

Lei Zhou, Ronald P. Hammer

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


The density of μ-opioid receptors is dependent upon the levels of gonadal steroid hormones in the medial preoptic area of ovariectomized female rats. Because the region containing these cyclical μ-opioid receptors is relatively small, autoradiographic analysis of the binding of a saturating concentration of μ-selective radioligand was used to determine whether hormone treatment affects maximal binding capacity of these receptors. The results reveal that gonadal steroid hormones upregulate μ-opioid receptor binding capacity specifically in the medial preoptic area 27 h later, without affecting binding in adjacent brain regions. This suggests that hormones induce a functional increase of medial preoptic area μ-opioid receptors which could serve to regulate reproductive activities.

Original languageEnglish (US)
Pages (from-to)271-274
Number of pages4
JournalEuropean Journal of Pharmacology
Issue number3
StatePublished - May 24 1995


  • Estrogen
  • Medial preoptic area
  • Progesterone
  • Upregulation
  • μ-Opioid receptor

ASJC Scopus subject areas

  • Pharmacology


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