Piccoli B, Parazzoli S, Zaniboni A, Demartini G, Fraschini F
Istituto di Medicina del Lavoro, Università di Milano.
Med Lav. 1991 May-Jun;82(3):213-32.
Artificial light which now plays an essential role in industrialized society differs from natural light both in intensity which is usually lower, and in spectrum, which is usually smaller. It is now a well-known fact that the human body is able to use luminous stimulation for aims other than sight; the pineal gland, though no longer directly sensitive to light as in lower animals, is nevertheless the fulcrum of a complex neuro-endocrine system which makes an interaction between light and the human body possible by means of the production of a number of substances of which melatonin is the most widely investigated. Melatonin is secreted at a circadian rhythm characterized by high nocturnal seric levels and low diurnal levels. This secretion appears to be correlated not only with the intensity of the light but also with its spectrum and time exposure. Even though the function of melatonin is still not fully understood, it seems possible to assign a mainly modulatory role to the pineal gland and melatonin. On the basis of studies performed on the pituitary-gonadal and/or hypothalamic axis and the reproductive system in animals, melatonin would appear to affect some endocrine functions (i.e., puberty) in man, too. Changes in melatonin secretion have been found in psychiatric illness, especially in cyclical affective disorders. Melatonin seems to be involved in stress-associated mechanisms, probably with an agonistic role, and also in carcinogenesis, where it seems to play a role in the growth of several tumors. Melatonin also affects both tumoral and cellular immune responses. Lastly, melatonin may be able to reduce the symptoms of the Jet Lag Syndrome. The consequences that prolonged and marked reduction in daylight exposure for occupational reasons could have on operators, especially young people, therefore constitute an interesting subject for occupational health; environmental photometry at the work-place, if adequately performed, could make a useful contribution to the development of this field of research.
在工业化社会中发挥着重要作用的人造光，在强度（通常较低）和光谱（通常较窄）方面都与自然光不同。现在众所周知的是，人体能够将光刺激用于视觉以外的目的；松果体虽然不再像低等动物那样直接对光敏感，但它仍然是一个复杂的神经内分泌系统的支点，该系统通过产生多种物质（其中褪黑素是研究最广泛的）使光与人体之间的相互作用成为可能。褪黑素以昼夜节律分泌，其特点是夜间血清水平高，白天水平低。这种分泌似乎不仅与光的强度有关，还与光的光谱和暴露时间有关。尽管褪黑素的功能仍未完全了解，但似乎可以赋予松果体和褪黑素主要的调节作用。根据对动物垂体 - 性腺和/或下丘脑轴以及生殖系统进行的研究，褪黑素似乎也会影响人类的某些内分泌功能（如青春期）。在精神疾病中，特别是在周期性情感障碍中，发现了褪黑素分泌的变化。褪黑素似乎参与了与压力相关的机制，可能起激动作用，还参与了致癌过程，在其中它似乎在几种肿瘤的生长中发挥作用。褪黑素还会影响肿瘤和细胞免疫反应。最后，褪黑素可能能够减轻时差综合症的症状。因此，由于职业原因导致白天光照时间长期显著减少对操作人员，尤其是年轻人可能产生的影响，构成了职业健康领域一个有趣的研究课题；工作场所的环境光度测量如果执行得当，可为该研究领域的发展做出有益贡献。
