HYPOPHYSIOTROPIC NEURON DIFFERENTIATION--TARGET FEEDBACK

拟议研究的广泛和长期目标是确定如何 来自垂体前叶的目标激素信号影响分化 调节垂体功能的下丘脑神经元。这些研究 旨在阐明生长激素（GH）和催乳素 (PRL)生存和形态，转录激活， 限制促垂体神经元的基因表达。健康 该项目的相关性在于了解 靶向信号或中间神经营养因子影响程序性 神经元细胞死亡，突触连接和递质表达，而不是 只有在发展中，但在遗传疾病，创伤后，或在 老化的过程。研究将在动物模型中进行， 侏儒小鼠，表现出GH和PRL的遗传缺陷，提供 目标信号缺失影响的污垢评估，其中 激素治疗的影响将是生理性的，但不会因 内源性激素的存在。具体目标是确定（1） 促垂体神经元程序性细胞死亡是否被夸大，或 异常轴突形态发生，在GH和PRL的情况下，2） GH和PRL影响垂体神经元的部位和机制， 3）是否出现GH和PRL调节神经元的异常 是由于下丘脑固有的遗传缺陷， 原发性脑垂体突变总体实验设计为 比较未处理和处理过的侏儒和正常同胞小鼠， 在出生后的发育和成年期。所用的方法 具体目标I是a）神经束追踪和B）识别（通过 免疫细胞化学; ICC）的细胞活力（代谢）的蛋白质标记物 酶）和细胞死亡（立即早期基因），在未经处理的发展 小鼠和用神经营养因子（包括GH和PRL）处理的小鼠。 对于特定目标2，方法将是PRL、GH和IGF-I的定位 通过ICC和原位杂交（ISHH）在下丘脑和 对GH应答的表达c-fos的神经元的表型鉴定 或PRL治疗。具体目标3将通过检查表达 (by ISHH）和结构（通过限制性酶切分析和测序）， a）下丘脑和B）中艾姆斯侏儒突变的候选基因 脑垂体

The broad, long-term objective of the proposed research is to define how target hormonal signals from the anterior pituitary affect differentiation of hypothalamic neurons that regulate pituitary function. The studies are designed to elucidate the influence of growth hormone (GH) and prolactin (PRL) on survival and morphology, transcriptional activation, and restriction in gene expression in hypophysiotropic neurons. The health relatedness of the project is in understanding the mechanism by which target signals or intermediate neurotrophic factors affect programmed neuronal cell death, synaptic connectivity and transmitter expression, not only in development, but in genetic disease, following trauma, or in the process of aging. The studies will be conducted in an animal model, the dwarf mouse, that exhibits genetic deficiency of GH and PRL, providing for dirt assessment of the effect of absent target signals, and in which effects of hormone treatment will be physiological, but not complicated by the presence of endogenous hormone. The specific aims are to determine 1) whether hypophysiotropic neuron programmed cell death is exaggerated, or abnormal axon morphology occurs, in the absence of GH and PRL, 2) the sites and mechanisms of GH and PRL influence on hypophysiotropic neurons, and 3) whether the abnormalities in GH and PRL-regulating neurons arise from a genetic defect inherent in the hypothalamus, or occur in response to a primary pituitary mutation. The overall experimental design is comparison of untreated and hormone-treated dwarf and normal sibling mice, during postnatal development and as adults. The methods to be used for Specific Aim I are a) neuronal tract-tracing and b) identification (by immunocytochemistry; ICC) of protein markers of cell viability (metabolic enzyme) and cell death (immediate-early genes), in untreated developing mice and in mice treated with neurotrophic factors including GH and PRL. For Specific Aim 2, the method will be localization of PRL, GH and IGF-I receptors by ICC and in situ hybridization (ISHH) in hypothalamus and phenotypic identification of neurons which express c-fos in response to GH or PRL treatment. Specific Aim 3 will be addressed by examining expression (by ISHH) and structure (by restriction analysis and sequencing) of candidate genes for the Ames dwarf mutation, in a) hypothalamus and b) pituitary.