IMCL area density, but not IMCL utilization, is higher in women during moderate-intensity endurance exercise, compared with men
IMCL area density, but not IMCL utilization, is higher in women during moderate-intensity endurance exercise, compared with men
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DOI：
10.1152/ajpregu.00510.2007
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发表时间：
2007-12-01
影响因子：
2.8
通讯作者：
Tarnopolsky, Mark A.
中科院分区：
文献类型：
--
作者：
Devries, Michaela C.;Lowther, Stuart A.;Tarnopolsky, Mark A.
女性在耐力运动中消耗更多的脂肪，这可以通过较低的呼吸交换率（RER）来证明。肌细胞内脂质（IMCL）在耐力运动中对脂质氧化的贡献是有争议的，研究IMCL利用率的性别差异发现了相互矛盾的结果。我们使用超微结构评估确定了性别对耐力运动回合中净IMCL使用的影响。男性（n = 17）和女性（n = 19）在63% V-O2峰值完成90分钟的自行车运动。在运动前后进行活检，并固定进行电子显微镜检查，以确定IMCL大小，IMCL/面积，IMCL面积密度和接触线粒体的IMCL %。运动时女性粗面内质网和碳水化合物氧化率低于男性，而脂质氧化率高于男性（P < 0.05）。女性IMCL面积和IMCL面积密度高于男性（P < 0.05）。女性运动后接触线粒体的% IMCL高于男性（P = 0.03）。运动减少IMCL面积密度（P = 0.01），由于IMCL/面积（P = 0.02）减少。IMCL大小或净使用无性别差异。总之，与男性相比，女性IMCL面积密度更高，这是由于# IMCL增加而不是IMCL大小增加，以及运动后接触线粒体的% IMCL增加。耐力运动导致IMCL密度的净减少，由于减少IMCL的数量，而不是减少IMCL的大小，在两种性别。
Women use more fat during endurance exercise as evidenced by a lower respiratory exchange ratio (RER). The contribution of intramyocellular lipid (IMCL) to lipid oxidation during endurance exercise is controversial, and studies investigating sex differences in IMCL utilization have found conflicting results. We determined the effect of sex on net IMCL use during an endurance exercise bout using an ultrastructural evaluation. Men (n = 17) and women (n = 19) completed 90-min cycling at 63% V-O2peak. Biopsies were taken before and after exercise and fixed for electron microscopy to determine IMCL size, # IMCL/area, IMCL area density, and the % IMCL touching mitochondria. Women had a lower RER and carbohydrate oxidation rate and a higher lipid oxidation rate during exercise (P < 0.05), compared with men. Women had a higher # IMCL/area and IMCL area density (P < 0.05), compared with men. Women, but not men, had a higher % IMCL touching mitochondria postexercise (P = 0.03). Exercise decreased IMCL area density (P = 0.01), due to a decrease in the # IMCL/area (P = 0.02). There was no sex difference in IMCL size or net use. In conclusion, women have higher IMCL area density compared with men, due to an increased # IMCL and not an increased IMCL size, as well as an increased % IMCL touching mitochondria postexercise. Endurance exercise resulted in a net decrease in IMCL density due to decreased number of IMCL, not decreased IMCL size, in both sexes.