Sex and regional differences in decrease of estrogen receptor α-immunoreactive cells by estrogen in rat hypothalamus and midbrain

Shunji Yamada, Daisuke Noguchi, Hiroyuki Ito, Korehito Yamanouchi

    Research output: Contribution to journalArticle

    30 Citations (Scopus)

    Abstract

    Sensitivity of neurons to estrogen in down-regulation of estrogen receptor α (ERα) can be thought to make a sex difference in regulatory system of reproductive activities. In this study, to investigate the sex difference of expression of ERα in the hypothalamus and midbrain, the number of ERα immunoreactive (-ir) cells was counted in orchidectomized (OCX) and ovariectomized (OVX) rats with or without treatment with estrogen. A week after the gonadectomy, 5 rats in each female and male were injected with 1 mg estradiol benzoate (EB). The remaining 5 rats in both sexes did not receive EB. The brain was fixed 24 h after EB-injection and 50 μm-serial frozen sections were made. After immunohistochemical staining for ERα, the number of ERα-ir cells was counted in a 0.2-mm2 frame in the anteroventral periventricular nucleus (AVPvN), the ventrolateral part of the ventromedial hypothalamic nucleus (vlVMN), the arcuate nucleus (ARCN), and the lateral mesencephalic central gray (lMCG) in 2 or 3 sections. The total number of ERα-ir cells was changed to a density value (number per 1 mm3). As the results, in EB-treated rats, the density of ERα-ir cells in all regions, except the male AVPvN and male lMCG, were lower than those in untreated rats of both sexes. In the vlVMN, the density of ERα-ir cells in OVX rats was higher than in OCX rats. These results suggest that there are sex and regional differences in the mechanisms of down-regulation of ERα by estrogen in the rat brain.

    Original languageEnglish
    Pages (from-to)135-139
    Number of pages5
    JournalNeuroscience Letters
    Volume463
    Issue number2
    DOIs
    Publication statusPublished - 2009 Oct 2

    Fingerprint

    Mesencephalon
    Sex Characteristics
    Estrogen Receptors
    Hypothalamus
    Estrogens
    Ventromedial Hypothalamic Nucleus
    Anterior Hypothalamus
    Periaqueductal Gray
    Down-Regulation
    Arcuate Nucleus of Hypothalamus
    Brain
    Frozen Sections
    Staining and Labeling
    Neurons
    Injections
    estradiol 3-benzoate

    Keywords

    • Down-regulation
    • Estrogen receptor α
    • Hypothalamus
    • Midbrain
    • Rat
    • Sex difference

    ASJC Scopus subject areas

    • Neuroscience(all)

    Cite this

    Sex and regional differences in decrease of estrogen receptor α-immunoreactive cells by estrogen in rat hypothalamus and midbrain. / Yamada, Shunji; Noguchi, Daisuke; Ito, Hiroyuki; Yamanouchi, Korehito.

    In: Neuroscience Letters, Vol. 463, No. 2, 02.10.2009, p. 135-139.

    Research output: Contribution to journalArticle

    Yamada, Shunji ; Noguchi, Daisuke ; Ito, Hiroyuki ; Yamanouchi, Korehito. / Sex and regional differences in decrease of estrogen receptor α-immunoreactive cells by estrogen in rat hypothalamus and midbrain. In: Neuroscience Letters. 2009 ; Vol. 463, No. 2. pp. 135-139.
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