Mullin J M, Diamond L, Kleinzeller A
J Cell Physiol. 1980 Oct;105(1):1-6. doi: 10.1002/jcp.1041050102.
Uptake of alpha-methyl-D-glucoside (AMG) by LLC-PK1 cells is inhibited by the uncoupler p-trifluoro-methoxyphenyl-hydrazone (FCCP) and by the absence of extracellular Na+, indicating that the transport system is energy- and Na+-dependent. We have previously demonstrated that transport of AMG by LLC-PK1 cells proceeds against a concentration gradient and is phlorizin-sensitive (Mullin et al., '80). Uptake of AMG was also inhibited by ouabain (OUA) but not by ortho-vanadate (VAN). Rubidium uptake also was affected by OUA but not by VAN. VAN, however, caused collapse of the three-dimensional domes of confluent LLC-PK1 monolayers much more rapidly and thoroughly than OUA. Since domes are presumably dependent upon the Na+ pump, yet VAN is not acting on transport-related functions of the OUA-sensitive (Na+ + K+)-ATPase, we hypothesize a direct effect of VAN on the water permeability of these cells. We also suggest that OUA does not act on these cells until domes collapse in normal course, and access of the OUA to the extracellular surface of antiluminal membranes is then achieved.
解偶联剂对三氟甲氧基苯腙（FCCP）以及细胞外无Na⁺时，LLC - PK1细胞对α - 甲基 - D - 葡萄糖苷（AMG）的摄取受到抑制，这表明该转运系统是能量和Na⁺依赖性的。我们之前已经证明，LLC - PK1细胞对AMG的转运是逆浓度梯度进行的，并且对根皮苷敏感（Mullin等人，1980年）。哇巴因（OUA）也抑制AMG的摄取，但原钒酸钠（VAN）则无此作用。铷的摄取也受OUA影响，但不受VAN影响。然而，VAN比OUA能更快、更彻底地导致汇合的LLC - PK1单层细胞的三维圆顶塌陷。由于圆顶大概依赖于Na⁺泵，而VAN并不作用于OUA敏感的（Na⁺ + K⁺）-ATP酶的转运相关功能，我们推测VAN对这些细胞的水通透性有直接影响。我们还认为，在正常情况下，直到圆顶塌陷，OUA才作用于这些细胞，然后OUA才能到达腔内膜的细胞外表面。
