Postprandial myofibrillar and whole body protein synthesis in young and old human subjects.
Postprandial myofibrillar and whole body protein synthesis in young and old human subjects.
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年轻和老年受试者的餐后肌原纤维和全身蛋白质合成。
DOI：
10.1152/ajpendo.1994.267.4.e599
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
McHenry,B
中科院分区：
文献类型：
--
作者：
Welle,S;Thornton,C;Statt,M;McHenry,B
以L-[1-13C]亮氨酸为示踪剂，测定了健康老年人(60岁，n=7)和青年(30岁，n=9)每隔30分钟进食小餐(每日能量的4%)的肌原纤维和全身蛋白质的掺入速率。青年组(148+/-5mmol.h-1)和老年组(150+/-3mmol.h-1)瘦体重-1 kg瘦体重(Means+/-SE)无差异。然而，老年组股外侧肌的肌原纤维蛋白合成速度慢28%(0.063±0.004比0.088±0.003%/h，P<；0.001)。将这些结果外推到全身肌原纤维合成(肌酸排泄率x肌原纤维质量的分数)表明，在老年组，总肌原纤维合成慢43%(1.8g/-0.2vs.3.1+/-0.2g/h，P<；0.01)，其肌原纤维合成在全身蛋白质合成中所占比例较小(15+/-1vs.23+/-1%，P<；0.001)。与年龄匹配的吸收后受试者相比，在这些喂养的受试者中，无论是年轻人还是老年人，全身蛋白质合成大约快25%，肌原纤维部分合成大约快50%。我们得出的结论是，在吸收后和餐后条件下，老年受试者的肌原纤维合成都较慢，但衰老并不会削弱喂养对蛋白质合成的刺激作用。
Rates of incorporation of leucine (using L-[1-13C]leucine as a tracer) into myofibrillar and whole body proteins were determined in healthy old (> 60 yr old, n = 7) and young (< 30 yr old, n = 9) men and women who were fed small meals (4% of daily energy) every 30 min. There was no difference in whole body incorporation of leucine into proteins in the young (148 +/- 5 mumol.h-1.kg lean body mass-1, means +/- SE) and old groups (150 +/- 3 mumol.h-1.kg lean body mass-1). However, the fractional myofibrillar protein synthesis in the vastus lateralis muscle was 28% slower in the older group (0.063 +/- 0.004 vs. 0.088 +/- 0.003 %/h, P < 0.001). Extrapolation of these results to whole body myofibrillar synthesis (fractional rate x myofibrillar mass estimated by creatinine excretion) indicated that, in the older group, total myofibrillar synthesis was 43% slower (1.8 +/- 0.2 vs. 3.1 +/- 0.2 g/h, P < 0.01) and that their myofibrillar synthesis was a smaller portion of whole body protein synthesis (15 +/- 1 vs. 23 +/- 1%, P < 0.001). Compared with age-matched postabsorptive subjects, whole body protein synthesis was approximately 25% faster, and fractional myofibrillar synthesis was approximately 50% faster in these fed subjects, both young and old. We conclude that myofibrillar synthesis is slower in older subjects during both postabsorptive and postprandial conditions but that aging does not impair the stimulatory effect of feeding on protein synthesis.