Data from: The size of a melanin-based plumage ornament correlates with glucocorticoid receptor concentrations in the skin of that ornament

Glucocorticoid hormones such as corticosterone (CORT) play crucial roles in many physiological processes. CORT's actions are primarily mediated via binding to two receptors (glucocorticoid receptors (GR) and mineralocorticoid receptors (MR)) in different target tissues. CORT receptors can be independently regulated from circulating hormone titers, from tissue to tissue and even within different regions of the same tissue type. Increasing evidence has shown relationships between circulating CORT and melanin-based pigmentation in skin and feathers, yet to our knowledge there have been no studies of CORT receptors in the skin of melanized ornaments. Male house sparrows (Passer domesticus) have a black, melanized bib, and evidence suggests that bib size is an important intraspecific signal. We examined the relationship between bib area and tissue sensitivity to CORT by quantifying GR and MR in bib skin and in adjacent paler-feathered belly skin (as a control tissue) at different life history stages using radioligand binding assays. Males with larger bibs relative to their life history stage had less GR in bib skin, but not belly skin, than males with smaller bibs. These results suggest a connection between the size of a melanin-based ornament and the underlying tissue's responsiveness to CORT.

糖皮质激素（Glucocorticoid hormones）如皮质酮（corticosterone, CORT）在诸多生理过程中发挥关键作用。CORT的生理活性主要通过在不同靶组织中结合两类受体——糖皮质激素受体（glucocorticoid receptors, GR）与盐皮质激素受体（mineralocorticoid receptors, MR）——来介导。CORT受体的调控可独立于循环激素滴度，且存在组织间差异，甚至在同一组织类型的不同区域间也存在差异。越来越多的研究表明，循环CORT水平与皮肤及羽毛的基于黑色素的色素沉着存在关联，但截至目前，尚无针对黑色素化装饰结构皮肤中CORT受体的相关研究。雄性家麻雀（Passer domesticus）具有黑色的黑色素化喉斑，已有研究提示喉斑大小是重要的种内信号。本研究通过放射性配体结合实验（radioligand binding assays），在不同生活史阶段定量检测喉斑皮肤及作为对照的相邻浅色羽毛腹部皮肤中的GR与MR含量，以此探究喉斑面积与组织对CORT的敏感性之间的关联。相较于处于相同生活史阶段的喉斑较小的雄性家麻雀，喉斑更大的个体其喉斑皮肤中的GR含量更低，而腹部皮肤中的GR含量无显著差异。上述结果表明，基于黑色素的装饰结构大小与其对应组织对CORT的响应性之间存在关联。