Vasopressin increases Na-K-2Cl cotransporter expression in thick ascending limb of Henle's loop.
To investigate whether the enhancement of thick ascending limb (TAL) NaCl transport in response to long-term increases in circulating vasopressin concentration is associated with increased expression levels of the apical Na-K-2Cl cotransporter in the rat TAL, we have carried out immunoblotting and immunofluorescence studies using affinity-purified, peptide-directed antibodies. Semiquantitative immunoblotting studies demonstrated a marked increase (193% of controls) in Na-K-2Cl cotransporter band density in response to restriction of water intake to 15 ml/day for 7 days. In contrast, the expression levels of two other apical proteins of the TAL (the type 3 Na/H exchanger and Tamm-Horsfall protein) were unchanged in the outer medulla. A 7-day subcutaneous infusion of the V2 receptor-selective vasopressin analog, 1-desamino-[8-D-arginine]vasopressin (DDAVP), to Brattleboro rats also markedly increased Na-K-2Cl cotransporter expression in the outer medulla (183% of controls). Immunofluorescence localization in outer medullary tissue sections confirmed the increase in Na-K-2Cl cotransporter expression in response to DDAVP. We conclude that vasopressin strongly upregulates the expression of the Na-K-2Cl cotransporter of the TAL and that it is likely to play an important role in the long-term regulation of the countercurrent multiplication system.
Kim
G H
GH
Laboratory of Kidney and Electrolyte Metabolism, National Heart, Lung, and Blood Institute, Bethesda, Maryland 20892, USA.
Ecelbarger
C A
CA
Mitchell
C
C
Packer
R K
RK
Wade
J B
JB
Knepper
M A
MA
D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D003894:Deamino Arginine Vasopressin / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D015151:Immunoblotting; D008138:Loop of Henle / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051381:Rats; D011910:Rats, Brattleboro; D017207:Rats, Sprague-Dawley; D012076:Renal Agents / Q000494:pharmacology; D028021:Sodium-Potassium-Chloride Symporters; D013997:Time Factors; D014667:Vasopressins / Q000494:pharmacology*; D014868:Water Deprivation / Q000502:physiology
D002352:Carrier Proteins; D012076:Renal Agents; D028021:Sodium-Potassium-Chloride Symporters; D014667:Vasopressins; D003894:Deamino Arginine Vasopressin