AJP - Renal Physiology, Vol 243, Issue 1 19-F22, Copyright © 1982 by American Physiological Society
Segmental analysis of sodium reabsorption during renal vein constriction
J. C. Burnett Jr, J. A. Haas and F. G. Knox
Clearance and micropuncture studies were performed in rats to identify the
nephron site(s) of altered sodium reabsorption during partial renal vein
constriction in the presence and absence of volume expansion. Renal vein
constriction increased fractional deliver of sodium to the late proximal
tubule from 52 +/- 3 to 61 +/- 4% in euvolemia and from 59 +/- 3 to 65 +/-
3% in volume expansion. In euvolemia, fractional delivery of sodium to the
early distal tubule was 13 +/- 3% before and 24 +/- 6% after renal vein
constriction. In volume expansion, fractional delivery of sodium to the
early distal tubule decreased from 15 +/- 3 to 9 +/- 2% in response to
renal vein constriction. We conclude that renal vein constriction decreases
sodium reabsorption by the proximal tubule both in euvolemia and in volume
expansion but that it increases sodium reabsorption by the superficial loop
of Henle only in the presence of volume expansion.
