Johannsson G, Bengtsson B A
Research Centre for Endocrinology & Metabolism, Sahlgrenska University Hospital, Göteborg, Sweden.
Horm Res. 1997;48 Suppl 5:72-7. doi: 10.1159/000191332.
Bone remodelling is a continuous, closely coupled process of bone resorption followed by bone formation. This process is regulated by factors and hormones which include GH, IGF-I and gonadal steroids. GH deficiency in childhood results in short stature and delayed bone maturation and a reduced peak bone mass might account for reduced BMC and BMD. Possible pathophysiological mechanisms for reduced bone mass in both childhood- and adult-onset GH deficiency are discussed. GH treatment effects on bone metabolism include increased remodelling, with increases in BMC, BMD and bone area. Increases in BMC and BMD are delayed while these changes are incorporated into the skeleton. BMC increases to a greater extent than BMD. At a cellular level, GH and IGF-I have direct and indirect effects on osteoblast and osteoclast precursors and fully differentiated cells. Osteoblasts possess both oestrogen and androgen receptors and bone loss accelerates with the loss of gonadal function. There are gender differences in GH effects on bone. BMD is related to fracture risk in the hip and lumbar spine in women. GH treatment might decrease fracture risk at a level comparable to oestrogen or bisphosphonate treatment. Patients with the lowest BMD prior to treatment derive the greatest benefit from GH therapy.
骨重塑是一个持续且紧密耦合的过程，先是骨吸收，随后是骨形成。这个过程受多种因素和激素调控，包括生长激素（GH）、胰岛素样生长因子-I（IGF-I）和性腺类固醇。儿童期生长激素缺乏会导致身材矮小、骨成熟延迟，骨量峰值降低可能是骨矿物质含量（BMC）和骨密度（BMD）降低的原因。本文讨论了儿童期和成年期起病的生长激素缺乏导致骨量减少的可能病理生理机制。生长激素治疗对骨代谢的影响包括重塑增加，同时BMC、BMD和骨面积增加。BMC和BMD的增加会延迟，因为这些变化要整合到骨骼中。BMC的增加幅度大于BMD。在细胞水平上，生长激素和胰岛素样生长因子-I对成骨细胞和破骨细胞前体细胞以及完全分化的细胞有直接和间接影响。成骨细胞同时拥有雌激素和雄激素受体，随着性腺功能丧失，骨质流失加速。生长激素对骨的影响存在性别差异。在女性中，BMD与髋部和腰椎的骨折风险相关。生长激素治疗可能会将骨折风险降低到与雌激素或双膦酸盐治疗相当的水平。治疗前BMD最低的患者从生长激素治疗中获益最大。
