Iowa State University, United States.
University of Padova, Italy.
Psychoneuroendocrinology. 2019 Mar;101:175-181. doi: 10.1016/j.psyneuen.2018.10.029. Epub 2018 Oct 28.
Saliva is a common noninvasive biofluid for measuring stress and sex hormones, yet one pressing limitation is that salivary hormones fluctuate momentarily, daily, and (for girls) across the menstrual cycle. Hair steroid assays are thought to provide a cumulative index which collapses across hormonal variability, potentially eliminating the confound of daily and menstrual cyclicity and thereby reflecting individual differences in average hormone levels. Here we seek to validate a hair bioassay methodology and test whether hair androgens accurately measure long-term, stable androgen levels in emerging adult women across two menstrual cycles.
Hair samples were collected at the end of each menstrual cycle for two cycles, and saliva samples were collected in the morning once per week across two menstrual cycles (N = 11 women). Hair samples were segmented by 1 cm for the first 4 cm to reflect the hormone levels of the past four serial months. Hair samples were assayed using commercially-available enzyme-immuno-assays for testosterone and DHEA.
Hair androgen concentrations were significantly correlated with averaged saliva hormone levels (DHEA: r = .75, p < .05; Testosterone: r = .67, p < .05). With respect to hair hormone stability, there were significant correlations for almost all the pairs of two 1 cm hair segments collected in two months that corresponded to the same time period. Hair androgens in one segment were significantly correlated with those in next segment. Regarding salivary androgen stability, the intra-class correlation across the weekly saliva samples indicated that for DHEA 59% of the total variance was within person and 41% was between person; and for testosterone 91% of the total variance was between person, and only 9% within person.
Results suggest that a one-time measure of hair provides a valid and reliable estimate of average steroid levels across two months. Moreover, whereas saliva measures of androgen levels capture week-to-week fluctuations in steroids, hair samples provide information on individual differences in average exposure to steroids, across long periods of time, such as months. Results are encouraging that hair DHEA and testosterone reflects the cumulative hormonal concentration and can be used as a stable hormonal index. Results also indicate that it is feasible to collect the first 3-4 centimeters of hair for studies of stable hormone levels.
唾液是一种常见的非侵入性生物体液，可用于测量应激和性激素，但一个紧迫的限制是，唾液激素会随时间波动，每日波动，（对于女孩而言）还会随月经周期波动。毛发类固醇检测被认为提供了一个累积指数，可以消除激素变异性、每日周期性和月经周期性的混杂因素，从而反映个体激素水平的差异。在这里，我们试图验证毛发生物检测方法，并测试毛发雄激素是否能准确测量两个月经周期中处于青春期的女性的长期稳定雄激素水平。
在两个月经周期的每个月经周期结束时采集头发样本，在两个月经周期中每周早上采集一次唾液样本（N=11 名女性）。通过 1 厘米的间隔将头发样本分成 4 厘米的段，以反映过去四个连续月份的激素水平。使用商业上可用的酶免疫测定法对睾酮和 DHEA 进行毛发样本检测。
毛发雄激素浓度与平均唾液激素水平显著相关（DHEA：r=0.75，p<0.05；睾酮：r=0.67，p<0.05）。关于毛发激素稳定性，在两个月内采集的几乎所有两段 1 厘米长的头发样本之间都存在显著相关性，这两段头发样本对应同一时间段。一段毛发中的雄激素与下一段毛发中的雄激素显著相关。关于唾液雄激素稳定性，每周唾液样本的组内相关表明，对于 DHEA，总方差的 59%是个体内差异，41%是个体间差异；对于睾酮，总方差的 91%是个体间差异，只有 9%是个体内差异。
结果表明，单次毛发测量可以提供两个月内平均类固醇水平的有效且可靠的估计。此外，虽然唾液雄激素水平测量可以捕捉类固醇的每周波动，但毛发样本提供了关于个体在较长时间内（如数月）对类固醇的平均暴露的差异信息。结果令人鼓舞，表明毛发 DHEA 和睾酮反映了累积的激素浓度，可以用作稳定的激素指标。结果还表明，采集 3-4 厘米长的头发用于稳定激素水平的研究是可行的。
