Loveys L S, Gelb D, Hurwitz S R, Puzas J E, Rosier R N
Department of Orthopaedics, University of Rochester, NY 14642.
J Orthop Res. 1993 Nov;11(6):884-91. doi: 10.1002/jor.1100110615.
Parathyroid hormone-related peptide (PTHrP) and parathyroid hormone (PTH) have similar biological effects in vitro that are mediated through the PTH receptor. PTH receptors have been demonstrated in the zone of provisional calcification and the hypertrophic zone of the cartilaginous growth plate. The current study examined the biological effects of PTHrP on chick growth plate chondrocytes. Chondrocytes were exposed to varying doses of PTHrP for 24 h, and the incorporation of radioactive thymidine into DNA was used as an index of proliferation. A dose-dependent stimulation of proliferation was seen, with a maximal 27-fold increase at 50 nM PTHrP. A dose-dependent stimulation of cAMP was seen, with a maximal effect at a dose of 50 nM. Proteoglycan synthesis, measured by incorporation of radioactive sulfate, was stimulated, with a maximal effect of 65% at 1 nM. Collagen synthesis and alkaline phosphatase activity from both cellular and matrix vesicle sources decreased in a dose-dependent fashion, with a maximal inhibition of approximately 50% of the control value. The physiologic significance of the PTH and PTHrP-responsiveness of growth plate chondrocytes is uncertain at the present time. It is possible that PTH or PTHrP, or both, act as a systemic, developmental modulator of cellular proliferation and differentiation in the growth plate.
甲状旁腺激素相关肽（PTHrP）和甲状旁腺激素（PTH）在体外具有相似的生物学效应，这些效应是通过PTH受体介导的。已在临时钙化区和软骨生长板的肥大区证实了PTH受体的存在。本研究检测了PTHrP对鸡生长板软骨细胞的生物学效应。将软骨细胞暴露于不同剂量的PTHrP中24小时，将放射性胸苷掺入DNA的情况用作增殖指标。观察到增殖呈剂量依赖性刺激，在50 nM PTHrP时最大增加27倍。观察到cAMP呈剂量依赖性刺激，在50 nM剂量时达到最大效应。通过掺入放射性硫酸盐测量的蛋白聚糖合成受到刺激，在1 nM时最大效应为65%。来自细胞和基质小泡来源的胶原蛋白合成和碱性磷酸酶活性呈剂量依赖性降低，最大抑制约为对照值的50%。目前，生长板软骨细胞对PTH和PTHrP反应性的生理意义尚不确定。有可能PTH或PTHrP，或两者都作为生长板中细胞增殖和分化的系统性发育调节剂。
