Clinic for Large Animals, Faculty of Veterinary Science, Szent István University, H-2225 Üllő - Dóra major, Hungary.
Domest Anim Endocrinol. 2013 Jul;45(1):38-42. doi: 10.1016/j.domaniend.2013.04.001. Epub 2013 May 4.
Daily fluctuations of cortisol concentration in the blood or saliva have been repeatedly reported. However, several contradictions in the existing literature appear on this subject. The present study was performed to definitively establish options for testing adrenocortical function. To the best of our knowledge, this is the first study to evaluate parallel circadian rhythms in salivary and serum cortisol concentrations during a 24-h period. Twenty horses were examined under the same conditions. Blood and saliva samples were taken every 2 h for 24 h to determine the daily changes in cortisol concentrations of saliva and serum at rest and to determine the relationship between salivary and serum cortisol levels. Cosinor analysis of group mean data confirmed a significant circadian component for both serum and salivary cortisol concentrations (P < 0.001 in both cases). The serum cortisol circadian rhythm had an acrophase at 10:50 AM (95% CI, 10:00 AM-11:40 AM), a MESOR of 22.67 ng/mL, and an amplitude of 11.93 ng/mL. The salivary cortisol circadian rhythm had an acrophase at 10:00 AM (95% CI, 9:00 AM-11:00 AM), a MESOR of 0.52 ng/mL, and an amplitude of 0.12 ng/mL. We found a significant but weak association between salivary and serum cortisol concentrations; the Pearson correlation coefficient was 0.32 (P < 0.001). The use of salivary cortisol level as an indicator of hypothalamic-pituitary-adrenal axis activity may be warranted. However, the salivary cortisol levels are more likely to be correlated with free plasma cortisol than with the total plasma cortisol concentration.
血液或唾液中的皮质醇浓度的日波动已被反复报道。然而，关于这个主题，现有的文献中存在一些矛盾。本研究旨在明确检测肾上腺皮质功能的检测选择。据我们所知，这是第一项评估唾液和血清皮质醇浓度在 24 小时期间平行的昼夜节律的研究。对 20 匹马进行了相同条件下的检查。采集了 24 小时内每 2 小时一次的血液和唾液样本，以确定休息时唾液和血清皮质醇浓度的日变化，并确定唾液和血清皮质醇水平之间的关系。对组均数数据的余弦分析证实了血清和唾液皮质醇浓度都存在显著的昼夜节律成分（两种情况均 P < 0.001）。血清皮质醇昼夜节律的高峰出现在上午 10:50（95%置信区间，上午 10:00-11:40），MESOR 为 22.67ng/mL，振幅为 11.93ng/mL。唾液皮质醇昼夜节律的高峰出现在上午 10:00（95%置信区间，上午 9:00-11:00），MESOR 为 0.52ng/mL，振幅为 0.12ng/mL。我们发现唾液和血清皮质醇浓度之间存在显著但较弱的相关性；Pearson 相关系数为 0.32（P < 0.001）。使用唾液皮质醇水平作为下丘脑-垂体-肾上腺轴活性的指标可能是合理的。然而，唾液皮质醇水平更可能与游离血浆皮质醇相关，而不是与总血浆皮质醇浓度相关。
