Pharmacological characterization of intracellular glucocorticoid receptors in nine tissues from house sparrow (Passer domesticus)

Christine R. Lattin, Kaiden Waldron-Francis, Joyce W. Richardson, Robert de Bruijn, Carolyn M. Bauer, Creagh W. Breuner, L. Michael Romero

    Research output: Contribution to journalArticlepeer-review

    53 Scopus citations

    Abstract

    Glucocorticoid hormones play a key role in the stress response, but plasma concentrations vary based on physiological, environmental, or social parameters. However, hormone titers alone do not determine organismal response. To enhance our understanding of glucocorticoid actions we can examine 'downstream' factors in the organismal stress response, measuring glucocorticoid receptors across target tissues. Here, we characterized intracellular binding sites for CORT (corticosterone, the avian glucocorticoid) in house sparrow (Passer domesticus) brain, liver, skeletal muscle, spleen, fat, testes, ovary, kidney and skin. We used radioligand binding assays to identify total capacity, relative density and affinity for CORT of intracellular receptors in each tissue. Most evidence supported two binding sites similar to mammalian low-affinity glucocorticoid receptor (GR) and a high-affinity mineralocorticoid receptor (MR) for brain, liver, kidney and testes, and only a GR-like receptor for muscle, spleen, fat, ovary and skin. However, kidney data were somewhat more complicated, possibly hinting at a mineralocorticoid function for CORT and/or GR in birds. In all tissues, GR and MR affinities were close to published house sparrow values (Kd∼6nM for GR, and ∼0.2nM for MR). Taken together, these data show that CORT receptor distribution appears to be as widespread in birds as it is in mammals, and suggest that independent regulation of peripheral receptors in different target tissues may play a role in CORT's diverse physiological effects.

    Original languageEnglish
    Pages (from-to)214-220
    Number of pages7
    JournalGeneral and Comparative Endocrinology
    Volume179
    Issue number2
    DOIs
    StatePublished - Nov 1 2012

    Keywords

    • Bird
    • Brain
    • Corticosterone
    • Glucocorticoid receptor
    • Mineralocorticoid receptor
    • Periphery

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