Effects of social cues on GnRH-I, GnRH-II, and reproductive physiology in female house sparrows (Passer domesticus)

Tyler J. Stevenson, George E. Bentley, Takayoshi Ubuka, Lutgarde Arckens, Elizabeth Hampson, Scott A. MacDougall-Shackleton

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    Abstract

    In all vertebrates, at least two forms of gonadotropin-releasing hormone (GnRH) are present: GnRH-I and GnRH-II. GnRH-I directly influences the reproductive axis whereas the function of GnRH-II is less clear. The present experimental objectives were to determine the effect(s) of male social cues on the peripheral and neural responses of female house sparrows (Passer domesticus). We hypothesized that male breeding status would significantly influence the amount of immunoreactive GnRH-II in female house sparrow brains. In order to test this hypothesis, females were caged with a breeding male, a non-breeding male, or caged alone. The presence of breeding males did not significantly influence ovary development, luteinizing hormone, or estradiol levels, but male presence increased female body mass, and male presence and condition interacted to influence ovarian follicle size. Using immunocytochemistry, GnRH-I and GnRH-II immunoreactivity was measured in order to evaluate the neuroendocrine response to breeding status in males. When females were housed with breeding males, there were stable numbers of immunoreactive GnRH-I and -II cells but significantly lower amounts of immunoreactive GnRH-I fibre staining within the preoptic area compared to females housed with non-breeding males. Moreover, immunoreactive GnRH-II fibres in the preoptic area, ventromedial nucleus, and medial septum were significantly greater in females housed alone in chamber with non-breeding males. The data demonstrate that the GnRH system in songbirds is modulated by social context. These finding provide novel insight into the mechanisms involved with regulating avian reproductive physiology.

    Original languageEnglish
    Pages (from-to)385-394
    Number of pages10
    JournalGeneral and Comparative Endocrinology
    Volume156
    Issue number2
    DOIs
    Publication statusPublished - 2008 Apr 1

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    Keywords

    • Breeding
    • GnRH-II
    • Immunocytochemistry
    • LHRH
    • Reproduction
    • Social cues

    ASJC Scopus subject areas

    • Endocrinology

    Cite this

    Stevenson, T. J., Bentley, G. E., Ubuka, T., Arckens, L., Hampson, E., & MacDougall-Shackleton, S. A. (2008). Effects of social cues on GnRH-I, GnRH-II, and reproductive physiology in female house sparrows (Passer domesticus). General and Comparative Endocrinology, 156(2), 385-394. https://doi.org/10.1016/j.ygcen.2008.01.015