Analysis of hair cortisol concentrations (HCCs) is a promising method for monitoring long-term stress in mammals. However, previous measurements of HCCs in polar bears (Ursus maritimus) have yielded highly variable results, which are likely due to different methodological approaches. In this study, hair samples of zoo-housed polar bears were analyzed for cortisol with two independent immunoassays [an enzyme-linked immunoassay (EIA) and a chemiluminescence assay (CLIA)] and liquid chromatography–tandem mass spectrometry (LC–MS/MS). HCC measurements depended significantly on assay type applied, sample processing (cutting vs. powdering hair) and their interaction. Best agreement was observed between LC–MS/MS and CLIA (R² = 0.81 for powdered hair) and sample processing had a minor, albeit significant, effect on obtained HCC measurements in these assays (R² > 0.9). EIA measurements were consistently higher than with the other assays. HCC measurement was validated biologically for CLIA and LC–MS/MS in one male polar bear that experienced considerable stress for a prolonged period of time (> 18 weeks). Subsequently, by using the validated LC–MS/MS the measurement of cortisol could be complemented by the analysis of other steroids including cortisone, testosterone and progesterone levels from hair samples collected over a 9-month period (5–13 months) from six zoo-housed polar bears (five males, one female). No seasonal steroid variation was observed except in male progesterone levels. For all steroids except cortisone, a strong body region effect (neck or paw) was observed. Cortisol and cortisone, as well as progesterone and testosterone, concentrations were positively correlated. We show that hair steroid concentrations can be used to longitudinally measure stress and reproductive hormone axes in polar bears. The data established herein provide important basic information regarding methodology and study design for assessing hair steroid hormones.

毛发皮质醇浓度 (HCC) 的分析是监测哺乳动物长期压力的一种很有前途的方法。然而，先前对北极熊（Ursus maritimus）HCC 的测量产生了高度可变的结果，这可能是由于不同的方法学方法所致。在这项研究中，使用两种独立的免疫测定法[酶联免疫测定法 (EIA) 和化学发光测定法 (CLIA)] 和液相色谱-串联质谱法 (LC-MS/MS) 分析了动物园北极熊的毛发样本中的皮质醇。 ）。HCC 测量在很大程度上取决于应用的分析类型、样品处理（剪发与粉化头发）及其相互作用。在 LC-MS/MS 和 CLIA (R ² = 0.81 用于粉状头发）和样品处理对这些测定中获得的 HCC 测量值有轻微但显着的影响（R ² > 0.9)。EIA 测量值始终高于其他测定。HCC 测量在一只雄性北极熊的 CLIA 和 LC-MS/MS 上进行了生物学验证，该北极熊在很长一段时间内（> 18 周）经历了相当大的压力。随后，通过使用经过验证的 LC-MS/MS，皮质醇的测量可以通过分析其他类固醇（包括可的松、睾酮和黄体酮）来补充，这些类固醇来自六个动物园在 9 个月期间（5-13 个月）收集的头发样本-圈养的北极熊（五只雄性，一只雌性）。除男性黄体酮水平外，没有观察到季节性类固醇变化。对于除可的松之外的所有类固醇，观察到强烈的身体区域效应（颈部或爪子）。皮质醇和可的松，以及孕酮和睾酮，浓度呈正相关。我们表明，毛发类固醇浓度可用于纵向测量北极熊的压力和生殖激素轴。本文建立的数据提供了有关评估头发类固醇激素的方法和研究设计的重要基本信息。