HYPOPHYSIOTROPIC NEURON DIFFERENTIATION--TARGET FEEDBACK

描述：拟定的研究旨在检验以下假设： 垂体前叶激素作为发育神经营养信号， 下丘脑垂体调节（促垂体）神经元。 那个女人 这项研究的长期目标是阐明 这些内分泌信号影响促垂体神经元存活， 分化和轴突终末引导。 这些研究将在 使用两种具有自发垂体转录的侏儒小鼠， 因子突变导致无法产生生长激素（GH）， 催乳素（PRL），并显示伴随的神经元异常， 产生GH调节生长抑素和GH释放激素， 因此，在发育过程中缺乏信号的影响可能 不需要实验就可以评估，激素治疗可能是有选择性的， 和具体。 一般的实验设计是评价 在没有目标反馈的情况下的发展事件，以及 激素替代疗法对这些事件的影响 具体目标是确定，在 未处理和未处理的侏儒小鼠，1） 向垂体的轴突异常终止于 下丘脑正中隆起（ME）以及这种模式是否是退行性的， 采用顺行和逆行追踪，免疫细胞化学（ICC） 和电子显微镜（EM），包括轴突导向评估 分子和结构元件，2）是否程序性细胞死亡 生后发生在垂体DA神经元之间，通过凋亡的ICC 基因产物、核小体末端原位标记和EM，以及3）是否IGF-I 和GDNF分别是GH和PRL作用的介质，通过评估 使用原位杂交技术检测这些因子及其受体的表达 并测试其中一种因素是否可以替代激素替代品。 与调解人评估有关的是具体目标4， 检查GH和PRL作用的途径和机制，通过定位 GH和PRL受体，鉴定这些受体表达的JAK/STAT蛋白 激活，测量GH后即刻早期基因产物的表达 或PRL治疗，并鉴定显示受体的神经元表型 或激活，因为促垂体神经元刺激可能是间接的。

DESCRIPTION: The proposed studies are designed to test the hypothesis that anterior pituitary hormones act as developmental neurotrophic signals for hypothalamic pituitary-regulating (hypophysiotropic) neurons. The broad, long-term objective of the research is to elucidate the mechanisms by which these endocrine signals affect hypophysiotropic neuron survival, differentiation, and axon terminal guidance. The studies will be conducted using two types of dwarf mouse with spontaneous pituitary transcription factor mutations that result in failure to produce growth hormone (GH) and prolactin (PRL), and which show concomitant abnormalities in neurons that produce GH-regulating somatostatin and GH-releasing hormone, and PRL-inhibiting DA. Thus, the effect of absent signal during development may be assessed without experimentation, and hormone treatments may be selective and specific. The general experimental design is evaluation of developmental events in the absence of target feedback, and of effects of hormone replacement on these events. The specific aims are to determine, in naive and hormone-treated dwarf mice, 1) the extent to which hypophysiotropic axons terminate aberrantly outside of or within the hypothalamic median eminence (ME) and whether this pattern is regressive, using anterograde and retrograde tract tracing, immunocytochemistry (ICC) and electron microscopy (EM), including assessment of axonal guidance molecules and structural elements in ME, 2) whether programmed cell death occurs postnatally among hypophysiotropic DA neurons, by ICC of apoptotic gene products, nucleosome end-labeling in situ, and EM, and 3) whether IGF-I and GDNF are respective mediators of GH and PRL effects, by assessing expression of these factors and their receptors using in situ hybridization and testing whether either factor can substitute for hormone replacement. Related to the assessment of mediators is Specific Aim 4, further examination of pathways and mechanisms of GH and PRL effect, by localizing GH and PRL receptors, identifying the JAK/STAT proteins that these receptors activate, measuring the expression of immediate-early gene products after GH or PRL treatment, and identifying the neuronal phenotypes showing receptor or activation, because hypophysiotropic neuron stimulation may be indirect.