Marcus R
Aging Study Unit, Stanford University School of Medicine, Palo Alto, Calif., USA.
Horm Res. 1997;48 Suppl 5:60-4. doi: 10.1159/000191330.
Three processes occur in the skeleton; modelling during growth, fracture repair and remodelling. Remodelling is bone resorption coupled to bone formation, and alterations in the remodelling balance are the final pathway to bone loss. Therapeutic agents are now available to minimize the normal phenomenon of age-related bone loss and protect against osteoporotic fracture. These agents reduce the rate of bone resorption, have positive effects on bone mass and some reduce fracture rates. None, however, restore bone mineral to normal levels. GH has been considered for this role due to its positive effects in vitro and in vivo. GH-deficient adults have low BMD compared to healthy controls, and the reasons for this finding are discussed. A neglected factor is a measurement artefact from the use of DXA. Long-term GH therapy can lead to clinically important increases in BMD in GH-deficient adults. The results from studies of GH administration to healthy elderly populations are also presented. The small rise of lumbar BMD or maintenance of BMD at the hip seen in these studies are no better than results achieved with cheaper, easier to administer therapies. Investigation of other agents in the somatotrophic axis, are, however, potentially promising and warrant further investigation.
生长期间的塑形、骨折修复和重塑。重塑是骨吸收与骨形成的耦合，而重塑平衡的改变是骨质流失的最终途径。现在有治疗药物可将与年龄相关的骨质流失这一正常现象降至最低，并预防骨质疏松性骨折。这些药物可降低骨吸收速率，对骨量有积极影响，有些还能降低骨折率。然而，没有一种药物能将骨矿物质恢复到正常水平。由于生长激素（GH）在体外和体内都有积极作用，因此一直被考虑用于此用途。与健康对照组相比，生长激素缺乏的成年人骨密度较低，并讨论了这一发现的原因。一个被忽视的因素是使用双能X线吸收法（DXA）时的测量假象。长期生长激素治疗可使生长激素缺乏的成年人骨密度在临床上显著增加。还介绍了对健康老年人群给予生长激素的研究结果。这些研究中观察到的腰椎骨密度小幅升高或髋部骨密度维持情况，并不比使用更便宜、更易给药的疗法所取得的结果更好。然而，对生长激素轴上其他药物的研究可能很有前景，值得进一步研究。
