PURINES AND THE MAINTENANCE OF MEIOTIC ARREST

嘌呤和减数分裂停滞的维持

• 批准号: 2199492
• 负责人: STEPHEN M DOWNS
• 金额: $ 9.33万
• 依托单位: MARQUETTE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-12-01 至 1998-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2199492
• 关键词: adenosine; cyclic AMP; egg /ovum; follicle stimulating hormone; glucose metabolism; high performance liquid chromatography; hormone regulation /control mechanism; hypoxanthine phosphoribosyltransferase; hypoxanthines; laboratory mouse; meiosis; oogenesis; pentose phosphate shunt; phosphorylation; purine /pyrimidine metabolism; radiotracer

A major goal of my research program is to identify molecules and metabolic pathways that participate in the control of oocyte maturation in mammals. The current proposal will test the idea that modulation of purine metabolism has direct influence on the mechanisms controlling meiotic maturation and that glucose metabolism plays an important role in this control. Purines and their associated metabolic pathways have been implicated as important participants in the mechanisms controlling meiotic maturation. Results of experiments conducted during the current grant period have led to the hypothesis that hypoxanthine maintains meiotic arrest through a cooperative interaction with the purine de novo nucleotide-generating pathways. We have also investigated the involvement of different energy sources in oocyte maturation and have determined that the uptake and metabolism of glucose is required for gonadotropin-induced germinal vesicle breakdown in meiotically arrested cumulus cell-enclosed oocytes in vitro. Further preliminary work suggests that the positive action of gonadotropins may be mediated by the pentose phosphate pathway (PPP) but not glycolysis. We hypothesize that metabolism of glucose through the PP mediates the maturation-inducing effects of follicle-stimulating hormone (FSH) by its effects on purine metabolism. Phosphoribosylpyrophosphate, a compound whose levels rise with increased PPP activity, can serve as an important link between carbohydrate use as a model system the oocyte-cumulus cell complex isolated from immature mice that were primed 48th with pregnant mare serum gonadotropin. Part I will address the effects of FSH on both purine and glucose metabolism in the oocyte-cumulus cell complex as it relates to the meiotic status of the oocyte. By using radiolabeled purines, purine precursors and glucose, we will determine via biochemical assays and HPLC address analyses what metabolic changes occur prior, to and during, FSH-induced meiotic maturation. Part II will address how alteration of specific intermediary steps of the purine metabolic pathways affects other metabolic steps as well as the control of meiotic arrest. Attention will be focused on de novo purine synthesis, the purine salvage pathway, and the nucleoside phosphorylating pathways (ie, adenosine to ATP and guanosine to GTP). In all of these experiments the site of action will be determined by analyzing the oocyte and cumulus cells separately. The proposed experiments will help delineate specific purine metabolic pathways involved in the maintenance of meiotic arrest and in FSH-induced maturation and will help define the role of carbohydrate metabolism in these processes. These results will have important implications for both fertility and contraception, since each is affected by the ability of the oocyte to successfully initiate and complete meiotic maturation. The data will also benefit the development of in vitro systems where either meiotic arrest or completion of meiotic maturation is the desired endpoint.

我的研究计划的主要目标是识别分子和 参与卵母细胞成熟控制的代谢途径 在哺乳动物中。 当前的建议将测试调制的想法 嘌呤代谢对控制机制有直接影响 减数分裂成熟和葡萄糖代谢起着重要作用 在此控件中。 嘌呤及其相关的代谢途径具有 被认为是控制机制的重要参与者 减数分裂成熟。 在电流期间进行的实验结果 赠款时期导致了假设持续的假设 通过与Novo的合作互动来减数分裂逮捕 核苷酸产生途径。 我们还调查了 不同能源参与卵母细胞成熟，并具有 确定需要葡萄糖的摄取和代谢 促性腺激素诱导的生发囊泡分解在减数分裂中被捕 积云细胞封闭的卵母细胞体外。 进一步的初步工作 表明促性腺激素的积极作用可能是由 戊糖磷酸盐途径（PPP），但不是糖酵解。 我们假设这一点 通过PP的葡萄糖代谢介导了成熟的诱导 卵泡刺激激素（FSH）对嘌呤的影响 代谢。 磷酸磷酸磷酸磷酸盐，一种化合物的水平升高 随着PPP活动的增加，可以作为重要的联系 碳水化合物用作模型系统 从未成熟的小鼠中分离出来，该小鼠以怀孕母马排名第48 血清促性腺激素。 第一部分将解决FSH对两个的影响 卵母细胞 - 果实细胞复合物中的嘌呤和葡萄糖代谢 与卵母细胞的减数分裂状态有关。 通过使用放射性标记 嘌呤，嘌呤前体和葡萄糖，我们将通过生化确定 测定和HPLC地址分析是事先发生的代谢变化， 在FSH诱导的减数分裂成熟期间。 第二部分将解决如何 嘌呤代谢的特定中介步骤的改变 途径会影响其他代谢步骤以及减数分裂的控制 逮捕。 注意将集中于从头嘌呤合成， 嘌呤挽救途径和核苷磷酸化途径（即 腺苷至ATP和GUNOSINE至GTP）。 在所有这些实验中 作用部位将通过分析卵母细胞和积云来确定 细胞分开。 提出的实验将有助于描述特定的嘌呤代谢 维持减数分裂逮捕和FSH引起的途径 成熟并将有助于定义碳水化合物代谢的作用 这些过程。 这些结果将对两者都有重要影响 生育和避孕，因为每个人都受到的能力影响 卵母细胞成功启动并完成减数分裂成熟。 这 数据还将受益于体外系统的开发 减数分裂逮捕或减数分裂成熟是所需的 端点。