Psychophysiology and Stress Research Group, Psychology, School of Social Sciences, University of Westminster, 115 New Cavendish Street, London W1W 6UW, UK.
Psychophysiology and Stress Research Group, Psychology, School of Social Sciences, University of Westminster, 115 New Cavendish Street, London W1W 6UW, UK.
Psychoneuroendocrinology. 2019 May;103:249-258. doi: 10.1016/j.psyneuen.2019.01.023. Epub 2019 Jan 31.
Pulsatile ultradian secretion of cortisol, rarely studied in salivary data, has functional importance in hypothalamic pituitary adrenal (HPA) axis regulation. The first daily ultradian episode, the cortisol awakening response (CAR), was examined in healthy adults, in 5-min secretion rates of salivary cortisol from electronically monitored awakening time to 1.25 h. Aggregated rates revealed a cubic trend, with wave-length of almost exactly 1 h, as predicted from known ultradian periodicity. Peak secretion rate occurred 20-min post-awakening. Peak (20-min) to trough (59-min) amplitude (PTA) expressed a salient signal shape. Rates rose steeply to and from peak, and major secretion was packaged into a few 5-min intervals, inconsistent with normal or uniform distribution of 5-min rates, but consistent with known pulsatile cortisol delivery. Null hypotheses asserting normal or uniform distributions were rejected. Maximal rates overwhelmingly occurred before and minimal rates after 30-mins, with degree of extremity at each polarity significantly positively correlated. To demonstrate utility and reliability of PTA estimation in a clinically relevant domain, re- analyses of a previously published study were conducted. Data from only three saliva samples were used, given importance of cost considerations for many CAR researchers. Difference between mean rates before and after 30-min yielded a simple salience index, highly correlated with PTA derived from full 5-min interval data. CAR salience performed significantly better than traditional AUCi magnitude in discriminating control cases (higher inferred amplitude) and cases with Seasonal Affective Disorder (lower inferred amplitude). Evidence suggested that low AUCi may be more sensitive in identifying within-subject changes (e.g. more depressed mood in winter among SAD cases) and low CAR salience better at revealing enduring between-subjects associations (e.g. underlying disorder vulnerability). Since both PTA salience and AUCi magnitude can be analysed and compared using exactly the same data from the same commonly used saliva sampling points, further research is warranted into the importance of individual differences in patterns of cortisol delivery, not just how much is delivered.
皮质醇的脉冲超短周期分泌在唾液数据中研究甚少，但在下丘脑-垂体-肾上腺 (HPA) 轴调节中具有重要的功能意义。在健康成年人中，我们检查了第一个每日超短周期事件，即皮质醇觉醒反应 (CAR)，以 5 分钟为间隔，从电子监测的觉醒时间到 1.25 小时，测量唾液皮质醇的分泌率。聚合后的速率呈现出三次曲线趋势，波长几乎正好为 1 小时，这与已知的超短周期周期性一致。分泌峰值出现在觉醒后 20 分钟。峰值（20 分钟）到低谷（59 分钟）的振幅（PTA）呈现出显著的信号形状。速率在接近和远离峰值时急剧上升，主要分泌被包装在几个 5 分钟的间隔内，这与 5 分钟速率的正态或均匀分布不一致，但与已知的脉冲皮质醇输送一致。正常或均匀分布的零假设被拒绝。最大速率压倒性地出现在 30 分钟之前和之后，每个极性的极端程度与另一极性显著正相关。为了在临床相关领域展示 PTA 估计的实用性和可靠性，对以前发表的研究进行了重新分析。由于许多 CAR 研究人员都重视成本考虑，因此仅使用了三个唾液样本的数据。在 30 分钟之前和之后的平均速率之间的差异产生了一个简单的显着性指数，与从完整的 5 分钟间隔数据得出的 PTA 高度相关。CAR 的显着性在区分对照病例（更高的推断振幅）和季节性情感障碍病例（更低的推断振幅）方面表现得明显更好。有证据表明，低 AUCi 可能更敏感于识别个体内的变化（例如，季节性情感障碍病例在冬季情绪更低落），而低 CAR 显着性则更好地揭示了个体间的持久关联（例如，潜在的疾病易感性）。由于 PTA 显着性和 AUCi 幅度都可以使用完全相同的数据，并且可以使用相同的来自相同常用唾液采样点的数据进行分析和比较，因此有必要进一步研究皮质醇输送模式的个体差异的重要性，而不仅仅是输送的量。
