Carpentier J L, Fehlmann M, Van Obberghen E, Gorden P, Orci L
Diabetes. 1985 Oct;34(10):1002-7. doi: 10.2337/diab.34.10.1002.
In the present experiments, we have correlated the distribution of 125I-insulin on the surface of rat hepatocytes with the dissociation of 125I-insulin from the cell. When 125I-insulin interacts with isolated rat hepatocytes at 15 degrees C, an increasing proportion of the bound ligand becomes nondissociable under the influence of acid pH (6.0), trypsin (0.5 mg/ml), or an excess of unlabeled insulin (10(-6) M). Under these conditions, only a small percentage of the labeled material is internalized as determined by quantitative electron microscope (EM) autoradiography. This progressive nondissociability of the ligand parallels its movement from microvilli to coated pits and its progressive concentration in these later surface specializations. These data suggest that receptors in different domains of the plasma membrane may have different dissociation rates for the ligand.
在当前实验中，我们已将125I - 胰岛素在大鼠肝细胞表面的分布与125I - 胰岛素从细胞上的解离相关联。当125I - 胰岛素在15℃与分离的大鼠肝细胞相互作用时，在酸性pH值（6.0）、胰蛋白酶（0.5mg/ml）或过量未标记胰岛素（10^(-6)M）的影响下，结合配体中越来越大比例的部分变得不可解离。在这些条件下，通过定量电子显微镜（EM）放射自显影测定，只有一小部分标记物质被内化。配体这种逐渐增加的不可解离性与其从微绒毛向被膜小窝的移动以及在这些后期表面特化结构中的逐渐浓缩相平行。这些数据表明质膜不同区域的受体对配体可能具有不同的解离速率。
