Effect of alterations in extracellular fluid volume on segmental sodium transport.

This review focuses on the segmental handling of sodium during alterations in extracellular fluid volume. There is abundant evidence that proximal tubular sodium reabsorption is inhibited by Ringer loading but there are also unequivocal data demonstrating that inhibition of a more distal nephron segment is required for a maximal natriuretic response. From the evidence at hand presently, it would seem that, of the distal nephron segments, only the collecting duct is inhibited by expansion of the extracellular volume per se.