Gronowicz G, Masur S K, Holtzman E
J Membr Biol. 1980;52(3):221-35. doi: 10.1007/BF01869191.
This study concerns the timing and magnitude of exocytosis and endocytosis in the granular cells of toad bladder during the hydroosmotic response to antidiuretic hormone. Granule exocytosis at the luminal cell surface is extensive within 5 min of the administration of a physiological dose of hormone. Hydroosmosis becomes detectable during this time period. The amount of membrane added to the luminal surface by exocytosis during 60 min of exposure to hormone can be of the same order of magnitude as the extent of the luminal plasma membrane. Endocytosis, demonstrated by peroxidase uptake from the luminal surface, becomes extensive during the period 15-45 min after hormone administration. Thus, maximal endocytic activity occurs later than the period of most extensive exocytosis and seems to correlate with the onset of the decline in water movement. The amount of membrane retrieved from the luminal surface by endocytosis during 60 min of stimulation is at least three quarters of that added by exocytosis. The bulk membrane movement in ADH stimulated preparations does not require the presence of an osmotic gradient. Colchicine inhibits the hydroosmotic response, the exocytosis of granules, and endocytosis at the luminal surface. These results strengthen our view that the bulk circulation of membrane at the cell surface, via exocytosis and endocytosis, is closely related to the permeability changes occurring at the surface.
本研究关注蟾蜍膀胱颗粒细胞在抗利尿激素引起的水渗透反应过程中胞吐作用和胞吞作用的时间及程度。给予生理剂量的激素后5分钟内，管腔细胞表面的颗粒胞吐作用广泛发生。在此时间段内可检测到水渗透作用。在暴露于激素60分钟期间，通过胞吐作用添加到管腔表面的膜量与管腔质膜的范围处于同一数量级。通过从管腔表面摄取过氧化物酶证明的胞吞作用，在激素给药后15 - 45分钟期间变得广泛。因此，最大胞吞活性出现在最广泛胞吐作用时期之后，并且似乎与水移动下降的开始相关。在刺激60分钟期间通过胞吞作用从管腔表面回收的膜量至少是通过胞吐作用添加的膜量的四分之三。抗利尿激素刺激的制剂中的大量膜运动不需要渗透梯度的存在。秋水仙碱抑制水渗透反应、颗粒的胞吐作用以及管腔表面的胞吞作用。这些结果强化了我们的观点，即通过胞吐作用和胞吞作用在细胞表面进行的大量膜循环与表面发生的通透性变化密切相关。
