60 HZ MAGNETIC FIELD--CLOCKS & REPRODUCTIVE DEVELOPMENT

描述（改编自申请人的摘要）：该提案将 确定60 Hz磁场（MF）暴露是否具有生物学效应 对生殖发育有害的影响。的 实验计划将部分定义MF暴露条件， 可能会影响到与中心相关的各种端点， 神经系统控制性成熟。 细胞和分子 标记物将被用来测试一个假设的机制， 暴露可能影响生殖发育。在Djungarian 仓鼠，青春期的过程可以诱导或逮捕 环境光周期 在漫长的日子里， 青春期的开始（15-25天）与快速的 性腺发育，促性腺激素分泌急剧增加， 内侧核中形态学单极GnRH神经元数量增加 大脑的视前区和斜角带区 每一个指数 由于暴露在短日照下， 这是由松果体褪黑激素的昼夜节律介导的 生产 MF暴露，在不同数量的物种，包括 已发现，Djungarian仓鼠，抑制夜间上升， 松果体褪黑激素的产生。 如果MF暴露对 褪黑激素节律具有生理意义，那么 传递光周期信息的机制将导致 生殖系统对短日照的不当反应。 实验计划集中在MF影响的机制， 褪黑激素与生殖发育 目的是确定 MF暴露是否影响内源性生物计时 产生褪黑激素节律的时钟或松果体本身。 脑和松果体对MF暴露的分子反应研究 腺包括转录激活，如表达 即刻早期基因c-fos和NGFIA，以及时钟相关基因 信息精氨酸加压素同系物的每一个基因。 进一步 考虑MF暴露对GnRH的直接细胞作用 神经元系统在青春期开始和在其个体发育导致， GnRH细胞数量、分布、形态、迁移和 在发展的关键阶段。 研究方法 使用已建立的动物模型系统来测试关于 MF暴露对生物计时的影响及其神经机制 控制着生殖发育

DESCRIPTION (Adapted from applicant's abstract):The proposal will determine whether 60-Hz magnetic field (MF) exposures have biological effects that are detrimental to reproductive development. The experimental plan, in part, will define the MF exposure conditions that may influence a variety of endpoints that are relevant to the central nervous system control of sexual maturation. Cellular and molecular markers will be used to test a hypothesis about the mechanism by which MF exposures may influence reproductive development. In the Djungarian hamster, the process of puberty can be induced or arrested by environmental photoperiod. In long days, a critical period for initiation of puberty (15-25 days of age) is associated with rapid gonadal development, a dramatic elevation in gonadotropin secretion and increased numbers of morphologically unipolar GnRH neurons in the medial preoptic and diagonal band regions of the brain. Each of these indices are maintained a prepubertal levels by exposure to short days, an effect that is mediated by the circadian rhythm in pineal gland melatonin production. MF exposure, in a diverse number of species, including the Djungarian hamster, has been found to suppress the night-time rise in pineal melatonin production. If the effect of MF exposure on the melatonin rhythm is of physiological significance, then a disruption in the mechanism that conveys photoperiod information will result in an inappropriate response to short days by the reproductive system. Experiments are planned to focus on the mechanism of MF effects on melatonin and reproductive development. The objective is to determine whether MF exposure affects timekeeping by the endogenous biological clock that generates the melatonin rhythm or on the pineal itself. Studies of the molecular responses to MF exposure in the brain and pineal gland include transcriptional activation, as indicated by the expression of the immediate early genes, c-fos and NGFIA, as well as clock-related messages for arginine vasopressin homologues of the per gene. Further consideration of a direct cellular action of MF exposure on the GnRH neuron system at the onset of puberty and during its ontogeny leads to studies of GnRH cell number, distribution, morphology, migration, and projections during critical stages of development. The research approach uses an established animal model system to test hypotheses about the effects of MF exposure on biological timekeeping and the neural mechanism that controls reproductive development.