McIntyre I M, Norman T R, Burrows G D, Armstrong S M
Department of Psychiatry, University of Melbourne, Austin Hospital, Heidelberg, Victoria, Australia.
Life Sci. 1989;45(4):327-32. doi: 10.1016/0024-3205(89)90142-2.
Plasma melatonin concentrations were examined following three relatively low intensities of artificial light. Six normal, healthy control subjects were all exposed to (a) 200 lux, (b) 400 lux and (c) 600 lux for a three hour duration from midnight to 0300 h. Blood was also collected on a control night where light intensity was less than 10 lux throughout. Significant suppression of melatonin was observed following light of 400 lux and 600 lux intensity when compared to the control night (p less than 0.05; Mann-Whitney U-test). 200 lux light did not produce a statistically significant melatonin suppression when compared with control samples. Each light intensity produced its own individual maximal melatonin suppression by one hour of exposure. Increased duration of exposure to the light had no further influence on melatonin plasma concentrations. These data confirm a dose response relationship between light and melatonin suppression, and indicate that there is no reciprocal relationship between the effects of light intensity and the duration of exposure on maximal melatonin suppression in man.
在三种相对较低强度的人造光照射后，检测了血浆褪黑素浓度。六名正常、健康的对照受试者均在午夜至03:00期间暴露于（a）200勒克斯、（b）400勒克斯和（c）600勒克斯的光照下，持续三小时。在一个对照夜晚也采集了血液，该夜晚的光照强度始终低于10勒克斯。与对照夜晚相比，在400勒克斯和600勒克斯强度的光照后观察到褪黑素受到显著抑制（p小于0.05；曼-惠特尼U检验）。与对照样本相比，200勒克斯的光照未产生统计学上显著的褪黑素抑制作用。每种光照强度在照射一小时时都会产生各自独特的最大褪黑素抑制效果。光照暴露时间的延长对血浆褪黑素浓度没有进一步影响。这些数据证实了光照与褪黑素抑制之间的剂量反应关系，并表明在人类中，光照强度的影响与暴露持续时间对最大褪黑素抑制作用之间不存在相互关系。
