Routes of epithelial water flow: aquaporins versus cotransporters.

ABSTRACT: The routes water takes through membrane barriers is still a matter of debate. Although aquaporins only allow transmembrane water movement along an osmotic gradient, cotransporters are believed to be capable of water transport against the osmotic gradient. Here we show that the renal potassium-chloride-cotransporter (KCC1) does not pump a fixed amount of water molecules per movement of one K(+) and one Cl(-), as was reported for the analogous transporter in the choroid plexus. We monitored water and potassium fluxes through monolayers of primary cultured renal epithelial cells by detecting tiny solute concentration changes in the immediate vicinity of the monolayer. KCC1 extruded K(+) ions in the presence of a transepithelial K(+) gradient, but did not transport water. KCC1 inhibition reduc

SUBMITTER: Mollajew R 

PROVIDER: S-EPMC2998630 | biostudies-literature | 2010 Dec

REPOSITORIES: biostudies-literature