Renal expression of aquaporins in liver cirrhosis induced by chronic common bile duct ligation in rats.
Semiquantitative immunoblotting was used to investigate the expression levels of the four major renal aquaporins, the Na-K-2Cl cotransporter of the thick ascending limb, the type 3 Na-H exchanger, and the Na-K-ATPase in kidneys from rats with cirrhosis secondary to common bile duct ligation (CBDL). These rats had significant water retention and hyponatremia. In contrast to models of cirrhosis induced by carbon tetrachloride, aquaporin-2 expression in CBDL-induced cirrhosis was decreased. Thus, these results show that in the setting of extracellular fluid volume expansion, excessive water retention with hyponatremia can occur in the absence of increases in aquaporin-2 abundance. In addition, the expression levels of the two basolateral collecting duct aquaporins (aquaporin-3 and -4) were decreased in CBDL rats relative to sham-operated control rats. Similarly, the Na-K-2Cl cotransporter of the thick ascending limb and the type 3 Na-H exchanger showed decreases in expression. In contrast, the expression levels of aquaporin-1 and the all subunit of the Na-K-ATPase were not decreased. Thus, dysregulation of multiple water channels and ion transporters may play a role in water balance abnormalities associated with CBDL-induced cirrhosis in rats.
Fernández-Llama
P
P
Laboratory of Kidney and Electrolyte Metabolism, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892-1603, USA.
Turner
R
R
Dibona
G
G
Knepper
M A
MA
D000818:Animals; D051399:Aquaporin 2; D051400:Aquaporin 3; D051401:Aquaporin 4; D051403:Aquaporin 6; D020346:Aquaporins / Q000378:metabolism*; D001834:Body Water / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D003135:Common Bile Duct; D004195:Disease Models, Animal; D015151:Immunoblotting; D007668:Kidney / Q000378:metabolism*; D008026:Ligation; D008106:Liver Cirrhosis, Experimental / Q000209:etiology / Q000378:metabolism*; D008297:Male; D011487:Protein Conformation; D051381:Rats; D017207:Rats, Sprague-Dawley; D000074083:Sodium-Hydrogen Exchanger 3; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism; D028021:Sodium-Potassium-Chloride Symporters; D000254:Sodium-Potassium-Exchanging ATPase / Q000737:chemistry / Q000378:metabolism
C496025:Aqp2 protein, rat; C496029:Aqp3 protein, rat; C496032:Aqp4 protein, rat; D051399:Aquaporin 2; D051401:Aquaporin 4; D051403:Aquaporin 6; D020346:Aquaporins; D002352:Carrier Proteins; D000074083:Sodium-Hydrogen Exchanger 3; D017923:Sodium-Hydrogen Exchangers; D028021:Sodium-Potassium-Chloride Symporters; D051400:Aquaporin 3; D000254:Sodium-Potassium-Exchanging ATPase