Larson M C, White B P, Cochran A, Donzella B, Gunnar M
Institute of Child Development, University of Minnesota, Minneapolis 55455-0345, USA.
Dev Psychobiol. 1998 Dec;33(4):327-37.
The decrease in responsiveness of the hypothalamic-pituitary-adrenocortical (HPA) system is marked over the first months of life. Seventy-eight healthy infants (44 girls), 7 to 15 weeks old, were given a laboratory mock physical examination. Salivary cortisol samples were collected pre- and postexamination and at home. Behavioral state during the examination and home sleep/wake activity were measured. Subjects younger than 11 weeks showed an increase in pre- to postexamination cortisol, while older subjects did not. Further, there was no decrease in behavioral distress to the examination with age. Infants who showed an early- morning peak (EMP) in home cortisol levels were significantly older and were likely to be those who slept through the night. However, the presence of an EMP was not associated with a lack of cortisol response to the examination. The decrease in cortisol responsiveness witnessed around the age of 3 months is presumably due to other processes associated with age, and not with the expression of the day-night rhythm in basal cortisol.
下丘脑-垂体-肾上腺皮质（HPA）系统的反应性在生命的最初几个月会显著下降。78名7至15周大的健康婴儿（44名女孩）接受了实验室模拟体格检查。在检查前、检查后以及在家中采集唾液皮质醇样本。测量了检查期间的行为状态以及在家中的睡眠/觉醒活动。11周以下的受试者检查前至检查后的皮质醇水平有所升高，而年龄较大的受试者则没有。此外，随着年龄增长，对检查的行为应激反应并没有降低。在家中皮质醇水平出现清晨峰值（EMP）的婴儿年龄显著较大，且很可能是那些夜间能持续睡眠的婴儿。然而，EMP的出现与对检查的皮质醇反应缺乏无关。3个月左右观察到的皮质醇反应性下降大概是由于与年龄相关的其他过程，而非基础皮质醇昼夜节律的表达。
