Isolated membrane vesicles as tools for analysis of epithelial transport.

In recent years a methodology has been developed to use vesicles of the isolated brush border and basolateral plasma membranes for intestinal transport studies. The methodology and information gained with the vesicle systems are discussed using the examples of nonelectrolyte transport. In particular, results are presented on the mechanisms of D-glucose and neutral amino acid translocation across both plasma membranes and the coupling of Na+ with sugar and amino acid transport in the brush-border membrane. Furthermore, the kinetic parameters of the Na+-dependent glucose transport system, determined with an equilibrium exchange procedure, and the effects of semistarvation on the transport properties of the brush border membrane are described.