Plasma triglyceride metabolism in humans and rats during aging and physical inactivity
Plasma triglyceride metabolism in humans and rats during aging and physical inactivity
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DOI：
10.1123/ijsnem.11.s1.s97
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发表时间：
2001-12-01
影响因子：
2.5
通讯作者：
Bey, L
中科院分区：
文献类型：
--
作者：
Hamilton, MT;Areiqat, E;Bey, L
身体活动往往随着年龄的增长而减少，因为日常生活的自发活动减少，而且锻炼强度降低。在对年轻大鼠的对照研究中，研究表明，与行走和站立相关的体力活动对于维持姿势性骨骼肌（慢收缩氧化肌）中高水平的脂蛋白脂肪酶（LPL）活性尤为重要。在跑步训练过程中，更强烈的收缩对于快速收缩糖酵解肌肉中的高LPL活性是重要的。衰老还导致骨骼肌LPL活性和承重骨骼肌中LPL蛋白的纤维类型特异性降低（并且在糖酵解肌肉中没有衰老效应）。因此，收缩不活动可能是一个重要因素，导致次优甘油三酯代谢骨骼肌在卸载在年轻的动物和老化。测量血浆LPL活性、血浆甘油三酯（TG）清除率、口服脂肪耐量试验后餐后高甘油三酯血症和空腹TG水平通常表明中老年血浆TG代谢降低。相比之下，与年龄匹配或年轻的对照组相比，接受过减肥训练的老年人具有良好的血脂水平，即使对照组没有超重。因此，经常与衰老相关的TG代谢不良可能是由一些降低年轻久坐个体骨骼肌LPL活性的相同过程引起的。
Physical activity often declines with age because of a reduction in the spontaneous activities of daily living and because of less intense exercise. In controlled studies of young rats, it was shown that physical activities associated with walking and standing were especially important for maintaining a high level of lipoprotein lipase (LPL) activity in postural skeletal muscles (slow-twitch oxidative muscles). More intense contractions during run training were important for a high LPL activity in the fast-twitch glycolytic muscles. Aging also causes a fiber type-specific decrease of skeletal muscle LPL activity and LPL protein in weight-bearing skeletal muscles (and no aging effect in glycolytic muscles). Thus, contractile inactivity may be a significant factor causing sub-optimal triglyceride metabolism in skeletal muscles during both unloading in young animals and aging. Measurements of plasma LPL activity, plasma triglyceride (TG) clearance rates, postprandial hypertriglyceridemia after oral fat tolerance tests, and fasting TG levels were generally indicative of reduced plasma TG metabolism during middle or old age. In contrast, older endurance-trained individuals had a favorable blood lipid profile compared to age-matched or young controls, even when the controls were not overweight. Therefore, the poor TG metabolism that is frequently associated with aging may be caused by some of the same processes that lower skeletal muscle LPL activity of young sedentary individuals.