Myofibrillar protein synthesis in young and old human subjects after three months of resistance training.
Myofibrillar protein synthesis in young and old human subjects after three months of resistance training.
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经过三个月的阻力训练后，年轻人和老年人受试者的肌原纤维蛋白合成。
DOI：
10.1152/ajpendo.1995.268.3.e422
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Statt,M
中科院分区：
文献类型：
--
作者：
Welle,S;Thornton,C;Statt,M
健康的老年男性和女性的肌肉蛋白质合成比年轻人慢，但这是否是由于相对废用而不是衰老造成的尚不清楚。本研究旨在检测年轻和老年男性和女性在3个月渐进式抗阻运动计划之前和之后的肌原纤维蛋白合成率。通过将示踪剂L-[1- 13 C]亮氨酸掺入通过针吸活检从股外侧肌获得的肌原纤维蛋白中来测定蛋白质合成。运动前，9名老年受试者（62-72岁，5名男性和4名女性）的平均肌原纤维合成分数比9名年轻受试者（22-31岁，5名男性和4名女性）慢33%（P < 0.01）。初始强度，确定由三次重复最大测试，是显着较低的老年组。力量和训练重量增加类似的年轻和老年组，当表示相对于基线值。在最后一次训练后的第二天测定训练后肌原纤维的合成。青年组和老年组训练后肌原纤维合成分数无明显变化，老年组仍比青年组慢27%（P < 0.05）。全身蛋白质周转率仅在年轻组中增加约10%，24小时尿3-甲基组氨酸排泄（肌原纤维蛋白水解的指数）没有受到训练的显着影响。这些数据表明，在老年受试者的较慢的肌原纤维合成率不能解释废用。
Muscle protein synthesis is slower in healthy older men and women than in young adults, but whether this results from relative disuse rather than aging is unclear. The present study was done to examine rates of myofibrillar protein synthesis before and after a 3-mo progressive resistance exercise program in young and old men and women. Protein synthesis was determined by incorporation of the tracer L-[1-13C]leucine into myofibrillar proteins obtained from the vastus lateralis muscle by needle biopsy. Before exercise, mean fractional myofibrillar synthesis was 33% slower (P < 0.01) in nine older subjects (62-72 yr old, 5 men and 4 women) than in 9 young subjects (22-31 yr old, 5 men and 4 women). Initial strength, as determined by three-repetition-maximum tests, was significantly less in the older group. Strength and training weights increased similarly in young and old groups, when expressed in relation to baseline values. Posttraining myofibrillar synthesis was determined on the day after the final training session. There was not a significant change in fractional myofibrillar synthesis in either the young or the old group after training, and the rate in the older group remained 27% slower (P < 0.05). Whole body protein turnover increased approximately 10% only in the younger group, and 24-h urinary 3-methylhistidine excretion (an index of myofibrillar proteolysis) was not significantly affected by training. These data suggest that the slower myofibrillar synthesis rate in older subjects cannot be explained by disuse.