COMBINED EFFECTS OF NUTRITIONAL AND EXERCISE COUNTERMEASURES

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。背景：这项实验将模拟宇航员在航天飞行中经历的许多身体状况，通过检测28天卧床期间抗阻运动(重量训练)、营养和应激激素(皮质醇)对肌肉的影响。具体目标和程序(摘要)：通过模仿宇航员在太空飞行期间的饮食，提供日常生活中正常摄入的大约80%的卡路里，确定抗阻运动和氨基酸补充相结合是否可以减少卧床28天期间的肌肉损失并保持肌肉功能。实验设计(总结)：本研究将包括年龄在18-50岁之间的正常健康受试者。受试者在参与之前将接受全面的筛查访问，并将由研究团队的多名成员进行评估。这项研究包括在GCRC住院36天，并进行了两项9小时的代谢研究。代谢研究将在卧床休息的第6天和第34天进行。皮质醇将在研究的28天卧床部分使用，以提高血液皮质醇水平，使其达到那些经历过航天飞行的人。受试者将被随机分配到六种实验条件中的一种(请参阅同意书的第二页)。研究结束两周后，受试者将被要求返回GCRC进行另外三次30分钟的后续访问。意义(摘要)：从这些研究中获得的信息将有助于更好地理解肌肉蛋白质代谢对运动、不活动和营养的反应机制。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Background: This experiment will simulate many of the physical conditions experienced by astronauts during spaceflight by examining the effects of resistance exercise (weight training), nutrition and a stress hormone (cortisol) on muscle during 28 days of bedrest. Specific Aims and Procedures (summary): To determine if a combination of resistance exercise and amino acid supplementation can reduce muscle loss and maintain muscle function during 28 days of bedrest by mimicking the diet of astronauts during spaceflight by providing approximately 80% of the calories normally ingested during daily life. Experimental Design (summary): This study will include normal healthy subjects between the ages of 18-50. Subjects will undergo a comprehensive screening visit prior to participating and will be assessed by multiple members of the research team. The study involves a 36-day in-patient stay in the GCRC with two nine hour metabolic studies. The metabolic studies will take place on days 6 and 34 of bedrest. Cortisol will be administered throughout the 28 day bedrest portion of the study to increase blood cortisol levels to those experienced in spaceflight. Subjects will be randomly assigned to one of six experimental conditions (please refer to page 2 of the consent form). Subjects will be required to return to the GCRC for three additional 30 minute follow-up visits two weeks following the study. Significance (summary): Information derived from these studies will allow a better understanding of the mechanisms involved in the response of muscle protein metabolism to exercise, inactivity, and nutrition.