AEROBIC EXERCISE AND PLASMA TRIGLYCERIDE CONCENTRATION

该子项目是利用NIH/NCRR资助的中心赠款提供的资源的许多研究子项目之一。子项目和研究者（PI）可能从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。所列机构为中心，不一定是研究者所在机构。吸收后和餐后血浆甘油三酯（TG）浓度升高与心血管疾病（CVD）增加相关。这表明血浆总TG负荷（24小时血浆TG浓度）是CVD的重要危险因素。虽然运动与降低心血管疾病有关，但其对血浆TG浓度和代谢的影响尚不清楚。1)运动对吸收后血浆TG浓度影响的研究数据相互矛盾。2)有很好的证据表明，运动降低了高脂餐后血浆TG浓度的上升。然而，运动对摄入典型混合餐后餐后血浆TG浓度的影响在很大程度上是未知的，运动对24小时血浆TG浓度的影响从未被研究过。3)运动对餐后TG降低作用的机制尚不清楚。本研究的主要目的是评估运动对24小时血浆TG浓度的影响，并确定运动诱导血浆TG浓度变化的潜在代谢机制。 我们假设：1）运动降低总24小时血浆TG浓度，主要是通过降低餐后血浆TG浓度，2）早晨运动对总24小时血浆TG浓度的影响大于晚上运动，3）运动诱导的餐后血浆TG浓度降低至少部分是由于餐后高胰岛素血症期间肝脏VLDL-TG分泌降低。为了检验我们的假设，我们将在24小时内每小时测量一次血浆TG浓度，并在休息和运动后血浆TG浓度升高的受试者的高胰岛素血症期间测量肝脏VLDL-TG分泌（通过使用稳定同位素标记的示踪技术）。从浓缩产生的数据，拟议的研究将提高我们的理解的代谢控制血浆TG浓度。此外，他们将帮助建立适当的指导方针，通过体力活动降低血浆TG浓度。

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. Elevated postabsorptive and postprandial plasma triglyceride (TG) concentrations are associated with increased cardiovascular disease (CVD). This suggest that total plasma TG load (24-hour plasma TG concentration) is an important risk factor for CVD. Although exercise is associated with decreased CVD, its effect on plasma TG concentration and metabolism is not clear. 1) Data from studies investigating the effects of exercise on postabsorptive plasma TG concentration are conflicting. 2) There is good evidence that exercise lowers the rise in plasma TG concentration after consumption of a single high-fat test meal. However, the effects of exercise on postprandial plasma TG concentration after ingestion of a typical mixed meal are largely unknown, and the effects of exercise on 24-hour plasma TG concentration has never been studied. 3) The mechanisms responsible for the postprandial TG-lowering effect of exercise remain unclear. The primary objectives of this proposal are to evaluate the effects of exercise on 24-hour plasma TG concentration, and to determine potential metabolic mechanisms responsible for the exercise-induced changes in plasma TG concentration. We hypothesize that: 1) Exercise decreases total 24-hour plasma TG concentration, predominately by lowering plasma TG concentration after meals, 2) Exercise in the morning has a greater effect on total 24-hour plasma TG concentration than exercise performed in the evening, and 3) The exercise-induced decrease in postprandial plasma TG concentration is, at least in part, due to lower hepatic VLDL-TG secretion during postprandial hyperinsulinemia. To test our hypothesis we will measure plasma TG concentration every hour for 24 hours and measure hepatic VLDL-TG secretion (by using stable isotope labeled tracer techniques) during hyperinsulinemia in subjects with increased plasma TG concentrations after rest and exercise. The data generated from concenration the proposed studies will improve our understanding of the metabolic control of plasma TG concentration. Furthermore, they will help establish appropriate guidelines to lower plasma TG concentration via physical activity.