Isgaard J, Möller C, Isaksson O G, Nilsson A, Mathews L S, Norstedt G
Department of Physiology, University of Göteborg, Sweden.
Endocrinology. 1988 Apr;122(4):1515-20. doi: 10.1210/endo-122-4-1515.
The mechanism of action for the stimulatory effect of GH on longitudinal bone growth is not yet clarified. Several recent reports indicate that GH has a direct effect at the site of the epiphyseal growth plate, as opposed to the somatomedin hypothesis which holds that the effect of GH is mediated by circulating insulin-like growth factors (IGFs). Using a RNA probe in a solution hybridization assay we investigated the presence of IGF-I mRNA in rat rib growth plate. Hypophysectomy resulted in a decrease in the number of IGF-I mRNA copies compared to that in normal rats. Replacement treatment with GH restored the number of transcripts in a specific and dose-dependent manner. The results show that GH regulates the level of IGF-I mRNA in rat rib growth plate and give further support to the hypothesis that locally produced IGF-I might contribute to the stimulatory effect of GH on longitudinal bone growth.
生长激素（GH）对纵向骨生长的刺激作用机制尚未阐明。最近的几份报告表明，GH在骨骺生长板部位具有直接作用，这与生长调节素假说相反，该假说认为GH的作用是由循环中的胰岛素样生长因子（IGFs）介导的。我们使用RNA探针在溶液杂交试验中研究了大鼠肋骨生长板中IGF-I mRNA的存在情况。与正常大鼠相比，垂体切除导致IGF-I mRNA拷贝数减少。用GH进行替代治疗以特异性和剂量依赖性方式恢复了转录本的数量。结果表明，GH调节大鼠肋骨生长板中IGF-I mRNA的水平，并进一步支持了局部产生的IGF-I可能有助于GH对纵向骨生长的刺激作用这一假说。
