Schneiderman R, Snir E, Popper O, Hiss J, Stein H, Maroudas A
Department of Biomedical Engineering, Julius Silver Institute of Biomedical Sciences, Technion-Israel Institute of Technology, Haifa.
Arch Biochem Biophys. 1995 Dec 1;324(1):159-72. doi: 10.1006/abbi.1995.9914.
Insulin-like growth factor-I (IGF-I) plays a major role in cartilage homeostasis. Our objective was to study the penetration of IGF-I, both alone and bound to serum proteins, into the different zones of normal human cartilage using radioactively labeled IGF-I. The uptake of free IGF-I was higher than that predicted on the basis of excluded volume calculations and showed concentration dependence: we attributed this to reversible binding of the hormone to the tissue. Since the extent of binding was much higher than that calculated for binding to cell receptors, we concluded that IGF-I binds to matrix components. The kinetics of desorption of IGF-I from cartilage confirmed our conclusions regarding binding. The degree of uptake of IGF-I protein complexes prepared by labeling human serum with [125I]IGF-I showed that such complexes are largely excluded from normal cartilage and that the amounts present in the tissue are too low to affect proteoglycan metabolism.
胰岛素样生长因子-I（IGF-I）在软骨内环境稳定中起主要作用。我们的目的是使用放射性标记的IGF-I研究单独的IGF-I以及与血清蛋白结合的IGF-I渗透进入正常人体软骨不同区域的情况。游离IGF-I的摄取高于基于排阻体积计算所预测的值，并且呈现浓度依赖性：我们将此归因于该激素与组织的可逆性结合。由于结合程度远高于计算得出的与细胞受体结合的程度，我们得出结论，IGF-I与基质成分结合。IGF-I从软骨解吸的动力学证实了我们关于结合的结论。用[125I]IGF-I标记人血清制备的IGF-I蛋白复合物的摄取程度表明，此类复合物在很大程度上被正常软骨排除在外，并且组织中存在的量过低，无法影响蛋白聚糖代谢。
