TY - JOUR
T1 - Pharmacological characterization of intracellular glucocorticoid receptors in nine tissues from house sparrow (Passer domesticus)
AU - Lattin, Christine R.
AU - Waldron-Francis, Kaiden
AU - Richardson, Joyce W.
AU - de Bruijn, Robert
AU - Bauer, Carolyn M.
AU - Breuner, Creagh W.
AU - Michael Romero, L.
N1 - Funding Information:
We would like to thank M. Aronovitz and M. J. Dickens for help with perfusions and C. Le, D. Keniston, and S. Lefebvre for help catching sparrows. This work was supported by an EPA STAR Fellowship to CRL, the National Science Foundation Research Experiences for Undergraduates program for JWR, and National Science Foundation (USA) Grant IOS-1048529 to LMR.
PY - 2012/11/1
Y1 - 2012/11/1
N2 - 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.
AB - 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.
KW - Bird
KW - Brain
KW - Corticosterone
KW - Glucocorticoid receptor
KW - Mineralocorticoid receptor
KW - Periphery
UR - http://www.scopus.com/inward/record.url?scp=84866290914&partnerID=8YFLogxK
U2 - 10.1016/j.ygcen.2012.08.007
DO - 10.1016/j.ygcen.2012.08.007
M3 - Article
C2 - 22926326
AN - SCOPUS:84866290914
SN - 0016-6480
VL - 179
SP - 214
EP - 220
JO - General and Comparative Endocrinology
JF - General and Comparative Endocrinology
IS - 2
ER -