Postel-Vinay M C, Corvol M T, Lang F, Fraud F, Guyda H, Posner B
Exp Cell Res. 1983 Oct;148(1):105-16. doi: 10.1016/0014-4827(83)90191-x.
Receptors for the insulin-like peptide ILAs have been identified in cultured rabbit chondrocytes. The cell-ILAs interaction is a time-dependent, reversible and saturable process. The cell-bound radioactive material appears as intact hormone. Insulin-like growth factor II (IGFII) is as potent as ILAs in competing for 125I-ILAs binding, whereas insulin-like growth factor I is somewhat less potent. Insulin does not affect ILAs binding. Our results suggest that the cultured chondrocytes possess a common receptor for the somatomedin peptides and that insulin, which is able to stimulate sulfate incorporation into proteoglycans, acts through an insulin receptor distinct from the somatomedin site. In growth plate chondrocytes the specific binding of 125I-ILAs is ten times lower than in articular cells in culture, whereas the sulfation activity of ILAs, at all concentrations studied, is 2.5-3 times lower in growth plate than in articular chondrocytes. The total binding of 125I-ILAs is higher to a particulate cell fraction than to intact cultured cells, by a factor of 10 for the growth plate cells, and by a factor of 2 for the articular cells. These findings suggest a poor accessibility of the hormone to the receptor sites of the growth plate chondrocytes in cultures, which are known to be surrounded by a thick matrix.
在培养的兔软骨细胞中已鉴定出胰岛素样肽ILA的受体。细胞与ILA的相互作用是一个时间依赖性、可逆且可饱和的过程。细胞结合的放射性物质呈现为完整的激素。胰岛素样生长因子II（IGFII）在竞争125I-ILA结合方面与ILA一样有效，而胰岛素样生长因子I的效力稍低。胰岛素不影响ILA的结合。我们的结果表明，培养的软骨细胞拥有一种生长调节素肽的共同受体，并且能够刺激硫酸盐掺入蛋白聚糖的胰岛素是通过一个与生长调节素位点不同的胰岛素受体起作用的。在生长板软骨细胞中，125I-ILA的特异性结合比培养的关节细胞低10倍，而在所研究的所有浓度下，ILA的硫酸化活性在生长板中比关节软骨细胞低2.5至3倍。125I-ILA与颗粒细胞部分的总结合高于与完整培养细胞的总结合，生长板细胞的总结合高10倍，关节细胞的总结合高2倍。这些发现表明，在培养物中，激素与生长板软骨细胞受体位点的可及性较差，已知生长板软骨细胞被厚厚的基质包围。
