a Behavioral and Metabolic Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada.
b Institut du savoir Montfort, Hôpital Montfort, Ottawa, ON K1K 0T2, Canada.
Appl Physiol Nutr Metab. 2018 Jul;43(7):727-732. doi: 10.1139/apnm-2017-0505. Epub 2018 Feb 21.
Circulating fatty acids are a major systemic energy source in the fasting state as well as a determinant of hepatic triglycerides (TG)-rich very-low-density lipoprotein production. Upon acute hypoxia, sympathetic arousal induces adipose tissue lipolysis, resulting in an increase in circulating nonesterified fatty acids (NEFA). Animal studies suggest that TG clearance may also be strongly reduced under hypoxia, though this effect has been shown to be dependent on temperature. Whether the hypoxia-induced rise in blood fatty acid concentrations affects fasting TG levels in humans under thermoneutral conditions remains unknown. TG, NEFA, and glycerol levels were measured in fasted healthy young men (n = 10) exposed for 6 h to either normoxia (ambient air) or acute hypoxia (fraction of inspired oxygen = 0.12) in a randomized, crossover design. Participants were casually clothed and rested in front of a fan in an environmental chamber maintained at 28 °C during each trial. Under hypoxia, a significantly greater increase in NEFA occurred (condition × time interaction, p = 0.049) and glycerol levels tended to be higher (condition × time, p = 0.104), suggesting an increase in adipose tissue lipolysis. However, plasma TG levels did not change over time and did not differ between the normoxia and hypoxia conditions. In conclusion, acute exposure to normobaric hypoxia under thermoneutral condition in healthy men during fasting state increased lipolysis without affecting circulating TG.
循环脂肪酸是禁食状态下的主要系统性能量来源，也是肝脏甘油三酯（TG）丰富的极低密度脂蛋白产生的决定因素。急性缺氧时，交感神经兴奋引起脂肪组织脂解，导致循环非酯化脂肪酸（NEFA）增加。动物研究表明，TG 清除率在缺氧下也可能显著降低，尽管这种效应取决于温度。在热中性条件下，缺氧引起的血液脂肪酸浓度升高是否会影响禁食 TG 水平在人类中尚不清楚。在一项随机交叉设计中，10 名健康年轻男性（n = 10）在环境室中暴露于常氧（环境空气）或急性缺氧（吸入氧分数 = 0.12）下 6 小时，空腹测量 TG、NEFA 和甘油水平。在每个试验中，参与者穿着便服，在环境室中面对风扇休息，环境室保持在 28°C。在缺氧条件下，NEFA 显著增加（条件×时间交互作用，p = 0.049），甘油水平趋于升高（条件×时间，p = 0.104），提示脂肪组织脂解增加。然而，血浆 TG 水平随时间没有变化，并且在常氧和缺氧条件之间没有差异。总之，在热中性条件下，健康男性在禁食状态下急性暴露于常压低氧会增加脂肪分解，而不会影响循环 TG。
