Pechinot D, Foucrier J, Feldmann G
J Cell Physiol. 1986 Dec;129(3):315-20. doi: 10.1002/jcp.1041290308.
It is generally considered that in exocytosis the size of the secreting cells does not increase when the membranes of exocytosis vesicles fuse with the plasma membrane. As the factors involved in the regulation of this phenomenon are poorly understood, we thought it worthwhile to investigate the relationship between the plasma membrane surface area and secretory activity. Isolated rat hepatocytes were prepared by liver collagenase perfusion. Secretion of the plasma protein, transferrin (Tf) was detected at the single cell level with specific anti-rat transferrin antibodies using the reverse hemolytic plaque test. Hepatocyte surface and hemolytic ring surface areas were calculated from diameters of hepatocyte and hemolytic plaque measured after 5h of incubation. A highly significant correlation was established between the plaque-forming hepatocyte surface areas and the corresponding hemolytic surface areas. This result was confirmed using an automatic image analysis method. Two-month-old rats were compared to 4-month-old rats. We observed that the ratio of the quantity of transferrin secreted by hepatocytes to the hepatocyte surface area was constant for a given incubation time, whatever the size of the hepatocytes. These results suggest that the plasma membrane surface area of hepatocytes may constitute a limiting factor in Tf secretion.
一般认为，在胞吐作用中，当胞吐小泡的膜与质膜融合时，分泌细胞的大小不会增加。由于对调节这一现象的相关因素了解甚少，我们认为研究质膜表面积与分泌活性之间的关系是值得的。通过肝脏胶原酶灌注制备分离的大鼠肝细胞。使用反向溶血空斑试验，用特异性抗大鼠转铁蛋白抗体在单细胞水平检测血浆蛋白转铁蛋白（Tf）的分泌。孵育5小时后，根据测量的肝细胞和溶血斑直径计算肝细胞表面积和溶血环表面积。在形成空斑的肝细胞表面积与相应的溶血表面积之间建立了高度显著的相关性。使用自动图像分析方法证实了这一结果。将2个月大的大鼠与4个月大的大鼠进行比较。我们观察到，在给定的孵育时间内，无论肝细胞大小如何，肝细胞分泌的转铁蛋白量与肝细胞表面积的比值是恒定的。这些结果表明，肝细胞的质膜表面积可能是Tf分泌的一个限制因素。
