Increased renal Na-K-ATPase, NCC, and beta-ENaC abundance in obese Zucker rats.
Renal sodium retention, as a result of increased abundance of sodium transporters, may play a role in the development and/or maintenance of the increased blood pressure in obesity. To address this hypothesis, we evaluated the relative abundances of renal sodium transporters in lean and obese Zucker rats at 2 and 4 mo of age by semiquantitative immunoblotting. Mean systolic blood pressure was higher in obese rats relative to lean at 3 mo, P < 0.02. Furthermore, circulating insulin levels were 6- or 13-fold higher in obese rats compared with lean at 2 or 4 mo of age, respectively. The abundances of the alpha(1)-subunit of Na-K-ATPase, the thiazide-sensitive Na-Cl cotransporter (NCC or TSC), and the beta-subunit of the epithelial sodium channel (ENaC) were all significantly increased in the obese rats' kidneys. There were no differences for the sodium hydrogen exchanger (NHE3), the bumetanide-sensitive Na-K-2Cl cotransporter (NKCC2 or BSC1), the type II sodium-phosphate cotransporter (NaPi-2), or the alpha-subunit of ENaC. These selective increases could possibly increase sodium retention by the kidney and therefore could play a role in obesity-related hypertension.
Bickel
C A
CA
Department of Medicine, Georgetown University, 4000 Reservoir Road NW, Washington, DC 20007, USA.
Verbalis
J G
JG
Knepper
M A
MA
Ecelbarger
C A
CA
D000818:Animals; D001794:Blood Pressure; D002352:Carrier Proteins / Q000378:metabolism*; D053503:Epithelial Sodium Channels; D006946:Hyperinsulinism / Q000378:metabolism; D007672:Kidney Cortex / Q000378:metabolism*; D008138:Loop of Henle / Q000378:metabolism; D008297:Male; D009765:Obesity / Q000378:metabolism*; D051381:Rats; D011924:Rats, Zucker; D012964:Sodium / Q000378:metabolism; D015222:Sodium Channels / Q000378:metabolism*; D012965:Sodium Chloride / Q000494:pharmacology; D049992:Sodium Chloride Symporters; D000074083:Sodium-Hydrogen Exchanger 3; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism; D050608:Sodium-Phosphate Cotransporter Proteins; D050610:Sodium-Phosphate Cotransporter Proteins, Type II; D028021:Sodium-Potassium-Chloride Symporters; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D027981:Symporters
D002352:Carrier Proteins; D053503:Epithelial Sodium Channels; C000613387:Slc9a3 protein, rat; D015222:Sodium Channels; D049992:Sodium Chloride Symporters; D000074083:Sodium-Hydrogen Exchanger 3; D017923:Sodium-Hydrogen Exchangers; D050608:Sodium-Phosphate Cotransporter Proteins; D050610:Sodium-Phosphate Cotransporter Proteins, Type II; D028021:Sodium-Potassium-Chloride Symporters; D027981:Symporters; D012965:Sodium Chloride; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase