Huang W H, Zheng M H
Department of Ortopaedic Surgery, University of Western Australia, Nedlands, Australia.
Histol Histopathol. 1999 Oct;14(4):1257-68. doi: 10.14670/HH-14.1257.
Steroid hormones have an important impact on bone. The mechanism of steroid action on bone cells is through an interaction with specific receptor proteins in the target cells. Steroid receptors are a class of molecules that function as both signal transducers and transcription factors. The receptors each have similar functional domains that are responsible for discrete functions. The mechanism of receptor action is mediated by both genomic and nongenomic pathways. It is believed that in genomic pathway the steroid passes through the cell membrane by passive diffusion and binds to the receptor within the nucleus. Steroids have direct action on osteoblasts via receptor, and the effects of steroids on osteoclastic bone resorption are mediated through osteoblasts which release soluble factors by the action of hormone-receptor binding. However, in addition to indirect effects on osteoclasts, the question whether steroid hormones could exert direct action on osteoclasts as well has not to be answered and findings to date are controversial. It is not doubt that understanding the precise molecular mechanism of steroid action on bone resorption will develop new approaches for the diagnosis and treatment of disease associated with osteoclastic bone resorption.
类固醇激素对骨骼有重要影响。类固醇对骨细胞的作用机制是通过与靶细胞中的特定受体蛋白相互作用。类固醇受体是一类兼具信号转导器和转录因子功能的分子。每个受体都有相似的功能结构域，负责不同的功能。受体作用机制由基因组和非基因组途径介导。据信，在基因组途径中，类固醇通过被动扩散穿过细胞膜并与细胞核内的受体结合。类固醇通过受体对成骨细胞有直接作用，类固醇对破骨细胞性骨吸收的影响是通过成骨细胞介导的，成骨细胞通过激素 - 受体结合作用释放可溶性因子。然而，除了对破骨细胞的间接影响外，类固醇激素是否也能对破骨细胞产生直接作用的问题尚未得到解答，迄今为止的研究结果存在争议。毫无疑问，了解类固醇对骨吸收作用的确切分子机制将为与破骨细胞性骨吸收相关疾病的诊断和治疗开发新方法。
