HUMAN PLASMA MELATONIN AND URINARY 6-SULPHATOXY MELATONIN - STUDIES IN NATURAL ANNUAL PHOTOPERIOD AND IN EXTENDED DARKNESS
HUMAN PLASMA MELATONIN AND URINARY 6-SULPHATOXY MELATONIN - STUDIES IN NATURAL ANNUAL PHOTOPERIOD AND IN EXTENDED DARKNESS
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DOI：
10.1111/j.1365-2265.1991.tb03491.x
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发表时间：
1991-07-01
影响因子：
3.2
通讯作者：
WANG, X
中科院分区：
文献类型：
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作者：
MATTHEWS, CD;GUERIN, MV;WANG, X
本研究的目的是：(1)检测自然光周期(35度-S)下人体血浆褪黑素的昼夜节律；(2)检测同一受试者在长时间黑暗条件下的褪黑素节律，以暴露光照的任何抑制(门控)效应；(3)严格研究血浆褪黑素与尿液代谢产物6-硫氧基褪黑素在一年中不同时间的关系。在24小时的间隔后，受试者在延长的黑暗条件下(自然日落前和自然日出后的5小时黑暗)继续进行类似的收集程序。研究对象包括4名(最少)至6名女性志愿者(年龄范围18-35岁)，她们有正常的生活方式，没有抑郁症病史，没有服用任何药物或最近从事轮班工作。测量采用放射免疫分析法检测血浆和尿样中的褪黑素含量。结果褪黑素的自然分泌在所有季节都推迟到日落后，但在夏季和在漫长的黑暗中日落的时间没有什么不同。自然条件下褪黑激素分泌的补偿在秋冬季日出时发生，但在春夏两季推迟到日出后，特别是在长时间黑暗中。褪黑激素分泌的持续时间在季节之间以及在自然光周期和延长黑暗条件下的分泌持续时间之间没有显著变化。6-硫氧基褪黑素的测定被证明是血浆褪黑素分泌的时相和幅度的密切指标。与血浆褪黑素可检测/不可检测的时间相比，6-硫氧基褪黑素的起效时间和起效时间均延迟。血浆褪黑素总分泌量与6-硫氧基褪黑素分泌量之间有很好的相关性。结论这一结果表明，只有在夏季黎明时才有光的抑制(门控)作用，这与每年这个时候褪黑素分泌的开始时间提前有关。环境光对褪黑素分泌缺乏主要的门控效应，正常携带的人类全年分泌持续时间不变，这突显了人类与季节性繁殖的光周期动物物种的差异。尿液6-硫氧基褪黑素在严格检查下被证明是血浆褪黑素水平的良好指标，并被证实是一种有用的临床措施。
OBJECTIVES The aims of the study were (1) to examine the human plasma melatonin rhythm at the equinoxes and the solstices in the natural photoperiod (at 35-degrees-S); (2) to examine melatonin rhythms in the same subjects under extended darkness conditions to expose any suppressive (gating) effects of light at any time of the year; (3) to undertake a rigorous examination of the relationship between plasma melatonin and the urinary metabolite 6-sulphatoxy melatonin at varying times of the year.DESIGN At the equinoxes and solstices, unrestricted subjects had hourly urine collections followed by venous blood sampling taken under natural light conditions for 24 hours. Following a 24 hour interval, a similar collection regime was performed with subjects held under conditions of extended darkness (5 hours darkness prior to natural sunset and following natural sunrise) for a further 24 hours.SUBJECTS Groups of four (minimum) to six female volunteers (age range 18-35 years) were studied, who had a normal lifestyle, no history of depression, and were not taking any medication or recently engaged in shiftwork.MEASUREMENTS The plasma was assayed for melatonin and the urine samples for 6-sulphatoxy melatonin by radioimmunoassay.RESULTS The onset of natural melatonin secretion was delayed until after sunset at all seasons but was earlier in summer, and not different from the time of sunset in extended darkness. The offset of melatonin secretion under natural conditions occurred at sunrise in autumn and winter but was delayed until after sunrise during spring and summer, particularly in extended darkness.No significant changes in the duration of melatonin secretion were observed between seasons nor between the duration of melatonin secretion under natural photoperiod or extended darkness.The measurement of 6-sulphatoxy melatonin proved to be a close indicator of the phase and amplitude of secretion of plasma melatonin. Both onset and off set times of 6-sulphatoxy melatonin were delayed compared to the times when plasma melatonin was detectable/undetectable. A good correlation exists between the total plasma melatonin secretion and that of 6-sulphatoxy melatonin.CONCLUSIONS The results suggest evidence for a suppressive (gating) effect of light at dawn only during summer which was associated with a phase advance of the onset of melatonin secretion at this time of year. The lack of a major gating effect of environment light on melatonin secretion, and the unchanging duration of secretion through the year in the normally entrained human, highlight differences between the human and those photoperiodic animal species which breed seasonally.Urinary 6-sulphatoxy melatonin proved to be a good indicator of plasma melatonin levels under rigorous examination and is confirmed as a useful clinical measure.