Meyer Jerrold, Novak Melinda, Hamel Amanda, Rosenberg Kendra
Department of Psychology, University of Massachusetts, Amherst.
J Vis Exp. 2014 Jan 24(83):e50882. doi: 10.3791/50882.
The stress hormone cortisol (CORT) is slowly incorporated into the growing hair shaft of humans, nonhuman primates, and other mammals. We developed and validated a method for CORT extraction and analysis from rhesus monkey hair and subsequently adapted this method for use with human scalp hair. In contrast to CORT "point samples" obtained from plasma or saliva, hair CORT provides an integrated measure of hypothalamic-pituitary-adrenocortical (HPA) system activity, and thus physiological stress, during the period of hormone incorporation. Because human scalp hair grows at an average rate of 1 cm/month, CORT levels obtained from hair segments several cm in length can potentially serve as a biomarker of stress experienced over a number of months. In our method, each hair sample is first washed twice in isopropanol to remove any CORT from the outside of the hair shaft that has been deposited from sweat or sebum. After drying, the sample is ground to a fine powder to break up the hair's protein matrix and increase the surface area for extraction. CORT from the interior of the hair shaft is extracted into methanol, the methanol is evaporated, and the extract is reconstituted in assay buffer. Extracted CORT, along with standards and quality controls, is then analyzed by means of a sensitive and specific commercially available enzyme immunoassay (EIA) kit. Readout from the EIA is converted to pg CORT per mg powdered hair weight. This method has been used in our laboratory to analyze hair CORT in humans, several species of macaque monkeys, marmosets, dogs, and polar bears. Many studies both from our lab and from other research groups have demonstrated the broad applicability of hair CORT for assessing chronic stress exposure in natural as well as laboratory settings.
应激激素皮质醇（CORT）会缓慢地融入人类、非人灵长类动物及其他哺乳动物不断生长的毛干中。我们开发并验证了一种从恒河猴毛发中提取和分析CORT的方法，随后将该方法应用于人类头皮毛发。与从血浆或唾液中获取的CORT“即时样本”不同，毛发CORT提供了激素融入期间下丘脑 - 垂体 - 肾上腺皮质（HPA）系统活动以及生理应激的综合测量值。由于人类头皮毛发平均每月生长1厘米，从几厘米长的毛发段中获得的CORT水平有可能作为数月来所经历应激的生物标志物。在我们的方法中，每个毛发样本首先用异丙醇洗涤两次，以去除毛发干外部从汗液或皮脂中沉积的任何CORT。干燥后，将样本研磨成细粉，以破坏毛发的蛋白质基质并增加提取的表面积。毛发干内部的CORT被提取到甲醇中，甲醇蒸发后，提取物在测定缓冲液中复溶。然后，提取的CORT与标准品和质量控制品一起，通过灵敏且特异的市售酶免疫分析（EIA）试剂盒进行分析。EIA的读数转换为每毫克毛发粉末重量中CORT的皮克数。该方法已在我们实验室用于分析人类、几种猕猴、狨猴、狗和北极熊的毛发CORT。我们实验室和其他研究小组的许多研究都证明了毛发CORT在评估自然环境以及实验室环境中慢性应激暴露方面的广泛适用性。
