INTRAMUSCULAR TRIGLYCERIDE TURNOVER AND INSULIN SENSITIVITY

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。我们的总体目标是阐明在休息、运动和恢复过程中肌内甘油三酯(IMTG)转化与胰岛素敏感性之间的关系。我们建议研究胰岛素敏感者(受过耐力训练的运动员)和不敏感者(II型糖尿病患者)。我们的目标是更好地理解这一悖论，即在II型糖尿病患者中，高浓度的IMTG与胰岛素敏感性呈负相关，而在耐力运动员中，IMTG浓度与胰岛素敏感性呈正相关。这项研究还将解决不同性别之间IMTG利用的潜在差异，并确定IMTG是否是训练有素的个人在运动期间的重要燃料来源。我们假设，与II型糖尿病患者相比，运动员在休息时、运动中和运动后IMTG的周转和利用都会增加。我们推测，在II型糖尿病患者中，增加的IMTG周转可以预防胰岛素减少的作用，这种作用通常伴随着IMTG储备的增加而出现。为了评估我们的假设，我们将招募受过耐力训练的运动员或II型糖尿病患者。胰岛素的作用将首先通过频繁抽样的静脉葡萄糖耐量试验来确定。然后，受试者将进行一项代谢研究，注入稳定的棕榈酸盐同位素，并在休息时进行肌肉活检，在50%最大摄氧量下运动1.5小时，然后在恢复期间进行2小时。然后，将使用示踪剂进入IMTG池的分数掺入率来计算IMTG周转率。

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. Our overall objective is to elucidate the relationship between intramuscular triglyceride (IMTG) turnover and insulin sensitivity during rest, exercise, and recovery. We are proposing to study insulin sensitive (endurance trained athletes) and insensitive individuals (Type II diabetics). We aim to better understand the paradox where high concentrations of IMTG are negatively associated with insulin sensitivity in Type II diabetes, yet positively associated with insulin sensitivity in endurance athletes. This study will also address potential differences in IMTG utilization between genders, and determine if IMTG is an important fuel source during exercise in trained individuals. We hypothesize IMTG turnover and utilization will be increased in athletes compared to Type II diabetics at rest, during, and after exercise. We postulate that increased IMTG turnover protects against the decreased insulin action commonly observed with increased IMTG stores in Type II diabetics. To evaluate our hypothesis we will recruit men and women who are either endurance trained athletes or Type II diabetics. Insulin action will first be determined via a frequently sampled intravenous glucose tolerance test. Subjects will then perform one metabolic study with an infusion of a stable isotope of palmitate and muscle biopsies during rest, 1.5 hours of exercise at 50% VO2max, and then during 2 hours of recovery. IMTG turnover will then be calculated using fractional incorporation rates of tracer into the IMTG pool.