Touitou Y
Service de Biochimie Médicale, Faculté de Médecine Pitié-Salpêtrière, Paris.
C R Seances Soc Biol Fil. 1998;192(4):643-57.
Melatonin (N-Acetyl-5-methoxytryptamine) is a hormone secreted mainly by the pineal gland or epiphyse and in smaller amounts by the retina. It is biosynthesized from tryptophan, the critical enzymatic step depends upon N-Acetyl-transferase (NAT). The circadian rhythm of melatonin is the same in man and all the laboratory animals studied until now with nocturnal plasma concentrations 3-10 times greater than during daytime. The secretion and release of melatonin depend upon a large number of exogenous and endogenous factors as e.g. sex, age, pubertal stage, menstrual cycle, drugs, season.... Light is the major regulating factor which acts through the retino-hypothalamic tract. Melatonin is considered as a transducer of the light signal forwarding to the organism the information about day length (relative length of day and night). It is a time-clue provider used by the organism to adapt itself to its environment.
褪黑素（N-乙酰-5-甲氧基色胺）是一种主要由松果体或松果体分泌的激素，视网膜也会分泌少量褪黑素。它由色氨酸生物合成，关键的酶促步骤取决于N-乙酰转移酶（NAT）。褪黑素的昼夜节律在人类和迄今为止研究的所有实验动物中都是相同的，夜间血浆浓度比白天高3至10倍。褪黑素的分泌和释放取决于大量的外源性和内源性因素，如性别、年龄、青春期阶段、月经周期、药物、季节……光通过视网膜-下丘脑束起作用，是主要的调节因素。褪黑素被认为是光信号的转换器，它将有关白天长度（昼夜相对长度）的信息传递给生物体。它是生物体用来适应环境的时间线索提供者。
