Show me the pathway! Regulation of paracellular permeability by Na+-glucose cotransport

The physiological impact of Na+-nutrient cotransport-dependent regulation o f intestinal tight junction permeability has been controversial. Nonetheles s, increased permeability of small intestinal mucosae and enterocyte tight junctions as a consequence of Na+-nutrient cotransport has been documented by a significant number of in vivo and in vitro studies. Some details of th e intracellular signaling events that regulate this process have been descr ibed recently. The aims of this article are to: (i) review studies of tight junction regulation and paracellular nutrient absorption in mammalian inte stine, (ii) identify potential applications of tight junction regulation, a nd (iii) summarize recent progress in defining molecular mechanisms that le ad to altered tight junction permeability. (C) 2000 Elsevier Science B.V. A ll rights reserved.