Astrocytes in the rat medial amygdala are responsive to adult androgens

Authors

  • Ryan T. Johnson,

    Corresponding author
    1. Neuroscience Program, Michigan State University, East Lansing, Michigan 48824-1101
    • Autism Research Training Program Fellow, the M.I.N.D. Institute, University of California, Davis, Sacramento, CA 95820
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  • Amanda Schneider,

    1. Neuroscience Program, Michigan State University, East Lansing, Michigan 48824-1101
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  • Lydia L. DonCarlos,

    1. Department of Cell and Molecular Physiology and the Neuroscience Institute, Loyola University Chicago, Stritch School of Medicine, Maywood, Illinois 60153
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  • S. Marc Breedlove,

    1. Neuroscience Program, Michigan State University, East Lansing, Michigan 48824-1101
    2. Psychology Department, Michigan State University, East Lansing, Michigan 48824-1101
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  • Cynthia L. Jordan

    1. Neuroscience Program, Michigan State University, East Lansing, Michigan 48824-1101
    2. Psychology Department, Michigan State University, East Lansing, Michigan 48824-1101
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Abstract

The posterodorsal medial amygdala (MePD) exhibits numerous sex differences including differences in volume and in the number and morphology of neurons and astroctyes. In adulthood, gonadal hormones, including both androgens and estrogens, have been shown to play a role in maintaining the masculine character of many of these sex differences, but whether adult gonadal hormones maintain the increased number and complexity of astrocytes in the male MePD was unknown. To answer this question we examined astrocytes in the MePD of male and female Long Evans rats that were gonadectomized as adults and treated for 30 days with either testosterone or a control treatment. At the end of treatment brains were collected and immunostained for glial fibrillary acidic protein. Stereological analysis revealed that adult androgen levels influenced the number and complexity of astrocytes in the MePD of both sexes, but the specific effects of androgens were different in males and females. However, sex differences in the number and complexity of adult astrocytes persisted even in the absence of gonadal hormones in adulthood, suggesting that androgens also act earlier in life to determine these adult sex differences. Using immunofluorescence and confocal microscopy, we found robust androgen receptor immunostaining in a subpopulation of MePD astrocytes, suggesting that testosterone may act directly on MePD astrocytes to influence their structure and function. J. Comp. Neurol. 520:2531–2544, 2012. © 2012 Wiley Periodicals, Inc.

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