Sharma M, Palacios-Bois J, Schwartz G, Iskandar H, Thakur M, Quirion R, Nair N P
Douglas Hospital Research Centre, Verdun, Quebec, Canada.
Biol Psychiatry. 1989 Feb 1;25(3):305-19. doi: 10.1016/0006-3223(89)90178-9.
The relationship of age to the circadian rhythms of melatonin and cortisol was investigated in 44 men and 27 women (age range 19-89 years). Subjects were physically and psychiatrically normal. Four hourly serial blood samples were drawn from 8:00 AM until 8:00 AM the next day, with additional samples at 10:00 PM and 2:00 AM. The indoor illumination was restricted to 300 lux during day and 50 lux during the night. Plasma melatonin and cortisol were estimated by radioimmunoassay. Results show that the means of melatonin and cortisol values decreased significantly with age when the subjects were divided into three age groups, i.e., 19-25 years, 42-65 years, and 66-89 years. They also showed a significant negative correlation with age. The acrophases of the two hormonal rhythms, however, showed different relationships to age. The acrophase of melatonin rhythm showed a positive correlation with age (r = 0.38, p less than 0.001), and cortisol showed a negative correlation with age (r = -0.56, p greater than 0.001). It is suggested that this may indicate a weakened responsiveness of the circadian system in the elderly to the day-night cycle and an altered relationship between the pacemakers driving melatonin and cortisol circadian rhythms. This may thus represent a biomarker for the intrinsic process of the aging of the brain.
在44名男性和27名女性（年龄范围19 - 89岁）中研究了年龄与褪黑素和皮质醇昼夜节律的关系。受试者身体和精神均正常。从上午8:00至次日上午8:00每四小时采集一次系列血样，晚上10:00和凌晨2:00额外采样。白天室内光照限制在300勒克斯，夜间限制在50勒克斯。采用放射免疫分析法测定血浆褪黑素和皮质醇。结果显示，当将受试者分为三个年龄组，即19 - 25岁、42 - 65岁和66 - 89岁时，褪黑素和皮质醇值的均值随年龄显著下降。它们与年龄也呈显著负相关。然而，两种激素节律的高峰相位与年龄呈现不同关系。褪黑素节律的高峰相位与年龄呈正相关（r = 0.38，p < 0.001），皮质醇与年龄呈负相关（r = -0.56，p > 0.001）。这表明这可能意味着老年人昼夜系统对昼夜循环的反应性减弱，以及驱动褪黑素和皮质醇昼夜节律的起搏器之间的关系发生改变。因此，这可能代表了大脑老化内在过程的一种生物标志物。
