Oestrogen upregulates noradrenaline release in the mediobasal hypothalamus and tyrosine hydroxylase gene expression in the brainstem of ovariectomized rhesus macaques

K. Y.F. Pau, D. L. Hess, S. Kohama, J. Bao, C. Y. Pau, H. G. Spies

    Research output: Contribution to journalArticle

    62 Scopus citations

    Abstract

    Noradrenaline plays a key role in the initiation of ovulation in nonprimate species. A similar noradrenaline role in the primate has not been established experimentally. We utilized the ovariectomized-oestrogen-supplemented (OVX + E) rhesus macaque to examine the effects of intravenous (i.v.) infusion of oestradiol-17β(E 2) on the activity of the brain noradrenaline system. Experiment 1 established the induction of a preovulatory surge-like release of luteinizing hormone in OVX+E monkeys by i.v. infusion of E 2 (OVX+E+E 2). In experiment 2, a marked increase in hypothalamic microdialysate noradrenaline concentrations occurred after identical E 2 infusion into the OVX + E monkeys that were used in experiment 1. In experiment 3, tyrosine hydroxylase (TH) mRNA expression in the locus coeruleus of the brainstem increased at various times after E 2 infusion as determined by semiquantitative in situ hybridization. The amount of TH mRNA in OVX + E + E 2 animals was higher (P < 0.05) than that in either the OVX + E or OVX monkeys; no difference was found in the latter two groups. Moreover, selected locus coeruleus sections from E 2-infused monkeys were examined for the localization of oestrogen receptors (ER) by in situ hybridization. Both ER-α and ER-β mRNAs were expressed in the locus coeruleus, although the expression was greater for ER-α than for ER-β. We conclude that i.v. infusion of E 2, which induces a preovulatory surge-like release of LH, stimulates brain noradrenaline activity; this enhanced activity likely involves an ER-mediated process and is reflected by hypothalamic noradrenaline release and locus coeruleus TH mRNA expression. The results support the concept that noradrenaline can influence the E 2-stimulated ovulation in nonhuman primates and that the brainstem is one of the components in this neuroendocrine process.

    Original languageEnglish (US)
    Pages (from-to)899-909
    Number of pages11
    JournalJournal of Neuroendocrinology
    Volume12
    Issue number9
    DOIs
    StatePublished - Sep 5 2000

    Keywords

    • Brainstem
    • Monkey
    • Noradrenaline
    • Oestrogen receptors
    • Tyrosine hydroxylase

    ASJC Scopus subject areas

    • Endocrinology, Diabetes and Metabolism
    • Endocrinology
    • Endocrine and Autonomic Systems
    • Cellular and Molecular Neuroscience

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