苯丙氨酸
内脏的
氨基酸
内科学
合成代谢
内分泌学
蛋白质分解代谢
化学
医学
肌肉蛋白
生物化学
血流
骨骼肌
作者
Elena Volpi,Bettina Mittendorfer,Steven E. Wolf,Robert R. Wolfe
出处
期刊:American Journal of Physiology-endocrinology and Metabolism
[American Physiological Society]
日期:1999-09-01
卷期号:277 (3): E513-E520
被引量:217
标识
DOI:10.1152/ajpendo.1999.277.3.e513
摘要
Muscle protein synthesis and breakdown and amino acid transport were measured in 7 healthy young (30 +/- 2 yr) and 8 healthy elderly (71 +/- 2 yr) volunteers in the postabsorptive state and during the oral administration of an amino acid mixture with L-[ring-(2)H(5)]phenylalanine infusion, femoral artery and vein catheterization, and muscle biopsies. Phenylalanine first-pass splanchnic extraction was measured by adding L-[ring-(13)C(6)]phenylalanine to the mixture. In the postabsorptive state, no differences in muscle amino acid kinetics were detected between young and elderly volunteers. Phenylalanine first-pass splanchnic extraction was significantly higher in the elderly (P < 0. 003) during ingestion of amino acids, but the delivery to the leg increased to the same extent in both groups. Phenylalanine transport into the muscle, muscle protein synthesis, and net balance increased significantly (P < 0.01) and similarly in both the young and the elderly. We conclude that, despite an increased splanchnic first-pass extraction, muscle protein anabolism can be stimulated by oral amino acids in the elderly as well as in the young.
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