Melatonin: Receptor-mediated events that may affect breast and other steroid hormone-dependent cancers
Melatonin: Receptor-mediated events that may affect breast and other steroid hormone-dependent cancers
复制标题
DOI：
10.1002/(sici)1098-2744(199803)21:3
复制
发表时间：
1998-03-01
影响因子：
4.6
通讯作者：
Barrett, JC
中科院分区：
文献类型：
--
作者：
Baldwin, WS;Barrett, JC
流行病学研究表明，极低频电磁场（EM Fs）与某些癌症的发病率增加之间可能存在联系。一种被认为与电磁场暴露有关的癌症是乳腺癌，据报道电工中的发病率增加。这些癌症关联很弱，与EMF暴露的联系仍然很脆弱。了解电磁场可能产生生物效应的机制将有助于阐明电磁场的风险（如果有的话）。一个受到相当关注的假设涉及电磁场降低褪黑激素水平。这一假说表明，褪黑激素的损失影响了各种激素的过程，如雌激素的稳态，从而可能增加乳腺癌的发病率。自从这一理论首次提出以来，假定的褪黑激素受体已被克隆，为研究褪黑激素的作用机制和褪黑激素假说提供了新的工具。这些受体存在于细胞的核和膜部分中。核受体（类维生素A Z受体）在脑和非神经组织中均被发现，而膜结合受体主要在神经组织中被发现，并且对褪黑激素具有更高的亲和力。这些受体可控制多种激素和免疫功能，包括从下丘脑和垂体释放促性腺激素以及B淋巴细胞中的5-脂氧合酶活性。这个工作假说简要回顾了我们目前对褪黑激素受体的认识，然后提供了褪黑激素受体失活如何导致癌症的理论，并提出了解决这个问题的研究领域。(C)1998 Wiley-Liss，Inc.
Epidemiological studies have suggested a possible link between extremely low frequency electromagnetic fields (EM Fs) and increased rates of certain cancers. One cancer that has been postulated to be associated with EMF exposure is breast cancer, for which increased rates have been reported among electricians. These cancer associations are weak, and the link to EMF exposures remains tenuous. Understanding the mechanisms by which EMFs could have biological effects will help in elucidating the risk, if any, from EMFs. One hypothesis that has received considerable attention involves reduction of melatonin levels by EMFs. This hypothesis suggests that loss of melatonin affects a variety of hormonal processes such as estrogen homeostasis and thereby may increase breast cancer rates. Since this theory was first presented, putative melatonin receptors have been cloned, providing new tools with which to examine melatonin's mechanism of action and the melatonin hypothesis. These receptors are found in nuclear and membrane fractions of cells. The nuclear receptors (retinoid Z receptors) are found both in the brain and in non-neural tissues, whereas the membrane-bound receptors are found primarily in neural tissue and have a higher affinity for melatonin. These receptors may control a variety of hormonal and immunological functions, including the release of gonadotropins from the hypothalamus and pituitary and 5-lipoxygenase activity in B lymphocytes. This Working Hypothesis briefly reviews our current knowledge of melatonin receptors and then provides theories on how the inactivation of melatonin receptors may cause cancer and suggests areas of research for addressing this question. (C) 1998 Wiley-Liss, Inc.