摘要：

The epithelial cell of the proximal renal tubule exhibits a typical morphological polarity, which parallels its functional differences. The apical cell pole facing the tubular lumen reveals numerous microvilli, while the contraluminal portion is characterized by basal infoldings, the "basal labyrinth" (BL) of the plasma-membrane (PM). Enzymes such as alanine-aminopeptidase (AAP), gamma-glutamyl transpeptidase (GGT), and alkaline phosphatase (AP) are found to be principal markers of the brush-border (BB). On the other hand, the presence of BL is associated with Na-K-ATPase activity. BB-membranes, which have been prepared by conventional separation techniques, might be contaminated with fragments of BL. Physiological, immunological, and other studies need reasonable purified material. This chapter reports the separation of BB and BL from human kidney cortex by buffer free flow electrophoresis. The results indicate different patterns of metabolic key enzymes and surface antigens on luminal and contraluminal PM of the proximal tubule.

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