Pituitary luteinizing hormone responses to single doses of exogenous GnRH in female social Cape ground squirrels exhibiting low reproductive skew

    Authors

    T. P. Jackson; J. M. Waterman;N. C. Bennett

    Comments

    Authors: contact us about adding a copy of your work at STARS@ucf.edu

    Abbreviated Journal Title

    J. Zool.

    Keywords

    luteinizing hormone; reproduction; ground squirrel; gonadotrophin-releasing hormone; DAMARALAND MOLE-RATS; XERUS-INAURIS; PUBERTY DELAY; LH RESPONSES; HETEROCEPHALUS-GLABER; CRYPTOMYS-DAMARENSIS; INDUCED INFERTILITY; SURICATA-SURICATTA; SUPPRESSION; SCIURIDAE; Zoology

    Abstract

    The Cape ground squirrel Xerus inauris is unusual among social mammals as it exhibits a low reproductive skew, being a facultative plural breeder with not all females breeding within a group. We investigated pituitary function to assess whether there was reproductive inhibition at the level of the pituitary and potentially the hypothalamus in breeding and non-breeding female Cape ground squirrels. We did so during the summer and winter periods by measuring luteinizing hormone (LH) responses to single doses of 2 g exogenous gonadotropin-releasing hormone (GnRH) and physiological saline administered to 42 females from 11 colonies. Basal LH concentrations of females increased in response to the GnRH challenge. Basal plasma LH concentrations were greater during winter, when most oestrus events are observed. However, we found no differences in plasma LH concentrations between breeding and non-breeding females. We showed that the anterior pituitary of non-breeding female ground squirrels is no less sensitive to exogenously administered GnRH than that of breeding females. We therefore concluded that the pituitary is no more active in breeding than non-breeding females. The lack of differentiation in response to GnRH suggests that either non-breeding females have ovaries that are less sensitive to LH or that they refrain from sexual activity with males through an alternative mechanism of self-restraint.

    Journal Title

    Journal of Zoology

    Volume

    273

    Issue/Number

    1

    Publication Date

    1-1-2007

    Document Type

    Article

    Language

    English

    First Page

    8

    Last Page

    13

    WOS Identifier

    WOS:000249429800002

    ISSN

    0952-8369

    Share

    COinS