Wehr T A
Section on Biological Rhythms, National Institute of Mental Health, Bethesda, MD, USA.
J Biol Rhythms. 2001 Aug;16(4):348-64. doi: 10.1177/074873001129002060.
Most of the anatomical and molecular substrates of the system that encodes changes in photoperiod in the duration of melatonin secretion, and the receptor molecules that read this signal, have been shown to be conserved in monkeys and humans, and the functions of this system appear to be intact from the level of the retina to the level of the melatonin-duration signal of change of season. While photoperiodic seasonal breeding has been shown to occur in monkeys, it remains unclear whether photoperiod and mediation of photoperiod's effects by melatonin influence human reproduction. Epidemiological evidence suggests that inhibition of fertility by heat in men in summer contributes to seasonal variation in human reproduction at lower latitudes and that stimulation of fertility by lengthening of the photoperiod in spring contributes to the variation at higher latitudes. Parallels between the seasonality of human reproduction and seasonal affective disorder suggest that they may be governed by common biological processes. Historical and experimental evidence indicates that human responses to seasonal changes in the natural photoperiod may have been more robust prior to the Industrial Revolution and that subsequently they have been increasingly suppressed by alterations of the physical environment.
在褪黑素分泌时长方面编码光周期变化的系统，其大部分解剖学和分子学基础，以及读取该信号的受体分子，已被证明在猴子和人类中是保守的，并且该系统的功能从视网膜水平到季节变化的褪黑素时长信号水平似乎都是完整的。虽然已证明猴子会出现光周期季节性繁殖，但光周期以及褪黑素对光周期效应的介导是否影响人类生殖仍不清楚。流行病学证据表明，夏季男性因高温导致生育能力受抑制，这在低纬度地区导致了人类生殖的季节性变化，而春季光周期延长对生育能力的刺激则在高纬度地区导致了这种变化。人类生殖季节性与季节性情感障碍之间的相似之处表明，它们可能受共同的生物学过程支配。历史和实验证据表明，在工业革命之前，人类对自然光周期季节性变化的反应可能更为强烈，而随后这些反应越来越受到物理环境变化的抑制。
