Yarasheski K E, Campbell J A, Kohrt W M
Division of Endocrinology and Metabolism, Washington University School of Medicine, St Louis, MO 63110, USA.
Clin Endocrinol (Oxf). 1997 Aug;47(2):223-9. doi: 10.1046/j.1365-2265.1997.2461060.x.
The purpose of this study was to evaluate whether 16 weeks of heavy resistance exercise training combined with daily growth hormone administration (GH) increases bone mineral density in 64-75-year-old men greater than resistance exercise training without GH supplementation.
Eighteen healthy, elderly men (67 +/- 1 year) followed a 16-week progressive resistance training programme (75-90% maximum strength, 5-10 repetitions/set, 4 sets/day, 4 days/week) after double-blind, random assignment to either a GH (12.5 or 18 micrograms/kg/day, equivalent to 25 or 36 mU/kg/day, n = 7) or placebo (n = 11) group.
Before and at the end of 16 weeks of resistance exercise with or without GH administration, body composition, whole body and regional bone mineral density (BMD) were determined by dual-energy X-ray absorptiometry. Serum osteocalcin and IGF-I were determined by radioimmunoassay before, during and at the end of treatment.
Increments in fat-free mass and training-specific maximum voluntary muscle strength were similar in both groups after training. Serum insulin-like growth factor-I (IGF-I) and osteocalcin levels were increased (P < 0.05) after exercise training plus GH. In comparison to initial measures, bone mineral density (g/cm2) of the proximal femur (Ward's triangle) was increased (P < 0.05) after 16 weeks of exercise training plus placebo treatment. Sixteen weeks of exercise training plus GH treatment did not increase whole body, spine or hip (femoral neck, trochanter, Ward's triangle) bone mineral density more than exercise plus placebo treatment.
These findings suggest that in these older men with normal bone mineral density, short-term resistance exercise training increased regional bone mineral density, but the addition of daily GH administration did not enhance whole body or regional bone mineral density despite GH-induced increments in serum IGF-I and osteocalcin. This implies that GH administration during a 16-week resistance exercise training programme may increase bone turnover without increasing bone mineral accumulation.
本研究旨在评估16周的高强度抗阻运动训练联合每日生长激素（GH）给药，相较于不补充GH的抗阻运动训练，是否能更大程度地提高64至75岁男性的骨密度。
18名健康老年男性（67±1岁）在双盲、随机分配至GH组（12.5或18微克/千克/天，相当于25或36毫单位/千克/天，n = 7）或安慰剂组（n = 11）后，进行了为期16周的渐进性抗阻训练计划（最大力量的75 - 90%，每组5 - 10次重复，每天4组，每周4天）。
在进行16周有或无GH给药的抗阻运动之前及结束时，通过双能X线吸收法测定身体成分、全身及局部骨密度（BMD）。在治疗前、治疗期间及结束时通过放射免疫分析法测定血清骨钙素和胰岛素样生长因子-I（IGF-I）。
训练后两组的去脂体重增加量和训练特异性最大随意肌力量相似。运动训练加GH后血清胰岛素样生长因子-I（IGF-I）和骨钙素水平升高（P < 0.05）。与初始测量值相比，运动训练加安慰剂治疗16周后，股骨近端（Ward三角区）的骨密度（克/平方厘米）增加（P < 0.05）。16周的运动训练加GH治疗在全身、脊柱或髋部（股骨颈、大转子、Ward三角区）骨密度增加方面并不比运动加安慰剂治疗更显著。
这些发现表明，在这些骨密度正常的老年男性中，短期抗阻运动训练可增加局部骨密度，但尽管GH诱导血清IGF-I和骨钙素升高，每日补充GH并未增强全身或局部骨密度。这意味着在为期16周的抗阻运动训练计划中给予GH可能会增加骨转换，但不会增加骨矿物质积累。
