Yarasheski K E, Zachwieja J J, Campbell J A, Bier D M
Metabolism Division, Washington University School of Medicine, St. Louis, Missouri 63110.
Am J Physiol. 1995 Feb;268(2 Pt 1):E268-76. doi: 10.1152/ajpendo.1995.268.2.E268.
The purpose of this study was to determine whether growth hormone (GH) administration enhances the muscle protein anabolism associated with heavy-resistance exercise training in older men. Twenty-three healthy, sedentary men (67 +/- 1 yr) with low serum insulin-like growth factor I levels followed a 16-wk progressive resistance exercise program (75-90% max strength, 4 days/wk) after random assignment to either a GH (12.5-24 micrograms.kg-1.day-1; n = 8) or placebo (n = 15) group. Fat-free mass (FFM) and total body water increased more in the GH group. Whole body protein synthesis and breakdown rates increased in the GH group after treatment. However, increments in vastus lateralis muscle protein synthesis rate, urinary creatinine excretion, and training-specific isotonic and isokinetic muscle strength were similar in both groups, while 24-h urinary 3-methylhistidine excretion was unchanged after treatment. These observations suggest that resistance exercise training improved muscle strength and anabolism in older men, but these improvements were not enhanced when exercise was combined with daily GH administration. The greater increase in FFM with GH treatment may have been due to an increase in noncontractile protein and fluid retention.
本研究的目的是确定给予生长激素（GH）是否能增强老年男性重阻力运动训练相关的肌肉蛋白合成代谢。23名血清胰岛素样生长因子I水平较低、健康且久坐不动的男性（67±1岁）在随机分为GH组（12.5 - 24微克·千克⁻¹·天⁻¹；n = 8）或安慰剂组（n = 15）后，进行了为期16周的渐进性阻力运动计划（最大力量的75 - 90%，每周4天）。GH组的去脂体重（FFM）和全身水含量增加更多。治疗后，GH组的全身蛋白质合成和分解率增加。然而，两组的股外侧肌蛋白质合成率、尿肌酐排泄以及训练特异性等张和等速肌力的增加相似，而治疗后24小时尿3 - 甲基组氨酸排泄未发生变化。这些观察结果表明，阻力运动训练改善了老年男性的肌肉力量和合成代谢，但当运动与每日给予GH相结合时，这些改善并未增强。GH治疗使FFM有更大增加可能是由于非收缩性蛋白质增加和液体潴留。
