Transport in Membrane Vesicles Isolated from the Mammalian Kidney and Intestine

Abstract

This chapter discusses the development of techniques for the isolation of the brush border and basal-lateral membranes and for the use of these membranes as model systems to examine the translocation of solutes and fluid. The kidney and intestine possess analogous transepithelial transport systems by which solutes common to the tubular and intestinal lumen enter the cell via the luminal brush border membrane and exit from the cell via the basal-lateral membrane. The renal basal-lateral membrane forms many interdigitating ridges and processes that significantly enlarge the area of the basal and lateral surfaces and increase the lateral intercellular spaces. The technique of free-flow electrophoresis of membranes has been adopted to separate the basal-lateral membranes from brush border microvillus membranes of intestinal epithelial cells. The plasma membranes are initially fragmented during homogenization of the cortex and the segments later separated by electrical charge