chapter  23
Chronic Adaptations of Na+/H+ Exchange in Renal Disease
ByLeon G. Fine, Edward P. Nord, Robert Gunther, Ira Kurtz
Pages 10

The renal proximal tubule absorbs the bulk of the filtered load of sodium and water and, as such, is the principal energy-consuming component of the kidney. The principal transport process which translocates filtered sodium from the lumen of the proximal tubule to the cell interior is Na+/H+ exchange 1 . When renal mass is reduced, or when disease alters glomerular function, tubular absorption of fluid adapts so that a relatively constant fraction of the filtered load is reclaimed 2 . This chapter examines the basis for this remarkable “cross-talk” between glomerulus and tubule and highlights the role of Na+/H+ antiport activity in mediating both the transtubular transport adaptation and the process of renal growth in the diseased kidney.