P2.179 Thursday, Jan. 5 Characterization of intracellular glucocorticoid and mineralocorticoid receptors in skin of House Sparrows WALDRON-FRANCIS, Kaiden*; LATTIN, Christine R.; BREUNER, Creagh W.; ROMERO, L. Michael; Tufts University; Tufts University; University of Montana-Missoula; Tufts University email@example.com
Corsticosterone (CORT) is responsible for a range of biological functions, including helping to mediate the stress response. Effects of CORT are controlled by hormone receptors, and by studying these receptors, we can further understand CORT’s role as a biological mediator. However, most investigations of receptors have focused on mammalian vertebrates and especially in neural tissue. Our knowledge of CORT receptors is lacking in other tissues from other taxa, especially avian peripheral tissues. Our study aimed to characterize levels of intracellular glucocorticoid (GR) and mineralocorticoid (MR) receptors in skin of wild House Sparrows (Passer domesticus) using radioligand binding assays. Competition assays were used to determine the displacement of [3H]CORT by unlabelled CORT, mifepristone (RU-486), and aldosterone (ALDO). Both CORT and ALDO were able to fully displace [3H]CORT, whereas RU-486 was not. We estimated dissociation constants (Kd) of MR and GR by saturation binding analysis. Skin cytosol exhibited a single-binding site with a Kd (~3.9 nM) similar to that previously reported for GR in House Sparrows. There appear to be minimal MR-like receptors in House Sparrow skin. The next steps following this preliminary characterization will include comparisons of receptor concentrations between individuals, as well as across different skin regions.