Aging is associated with elevated muscle triglyceride content and increased insulin-stimulated fatty acid uptake.
Aging is associated with elevated muscle triglyceride content and increased insulin-stimulated fatty acid uptake.
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DOI：
10.1152/ajpendo.00222.2002
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发表时间：
2003-10
期刊：
影响因子：
--
通讯作者：
M. Tucker;L. Turcotte
中科院分区：
文献类型：
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作者：
M. Tucker;L. Turcotte
本研究的目的是研究利用脂肪酸（FA）和肌肉基质的骨骼肌在年轻，中年和老年成年大鼠在高血糖和高胰岛素血症的条件下。对5、15或24月龄的雄性Fischer 344 x Brown Norway大鼠进行后肢灌注20 mM葡萄糖、1 mM棕榈酸盐、1，000 microU/ml胰岛素、[1- 14 C]棕榈酸盐和[3- 3 H]葡萄糖的培养基。各年龄组的葡萄糖摄取和棕榈酸酯输送相似。与5月龄和15月龄相比，24月龄的动物对棕榈酸的摄取和氧化以及脂肪酸移位酶（FAT/CD 36）和质膜脂肪酸结合蛋白（FABPPM）的肌肉蛋白浓度显著增加（P <或= 0.05）。与5月龄和15月龄动物相比，24月龄动物灌注前和灌注后肌肉甘油三酯（TG）水平显著升高（P < 0.05），在红色肌肉中升高72-145%，在白色肌肉中升高112-129%。棕榈酸摄取与灌注前总TG浓度（r2 = 0.27，P < 0.05）和总TG合成率（r2 = 0.68，P < 0.05）相关。这些结果表明，在胰岛素刺激的条件下，FA摄取显着增加，在老年动物，这是与TG合成的速率增加，并可能有助于TG在老年动物的肌肉中的积累。
The purpose of the present study was to examine the utilization of fatty acids (FA) and muscle substrates by skeletal muscle in young, middle-aged, and old adult rats under hyperglycemic and hyperinsulinemic conditions. Male Fischer 344 x Brown Norway rats aged 5, 15, or 24 mo underwent hindlimb perfusion with a medium of 20 mM glucose, 1 mM palmitate, 1,000 microU/ml insulin, [1-14C]palmitate, and [3-3H]glucose. Glucose uptake and palmitate delivery were similar among age groups. Palmitate uptake and oxidation as well as muscle protein concentration of fatty acid translocase (FAT/CD36) and plasma membrane fatty acid-binding protein (FABPPM) were significantly increased (P < or = 0.05) in 24- vs. 5- and 15-mo-old animals. Compared with 5- and 15-mo-old animals, pre- and postperfusion muscle triglyceride (TG) levels were significantly (P < 0.05) elevated 72-145% in red and 112-129% in white muscles of 24-mo-old animals. Palmitate uptake was associated with total preperfusion TG concentration (r2 = 0.27, P < 0.05) and total TG synthesis rate (r2 = 0.68, P < 0.05). These results indicate that, under insulin-stimulated conditions, FA uptake is significantly increased in old animals, which is associated with increased rates of TG synthesis and may contribute to the accumulation of TG in muscle of old animals.