Vasopressin-mediated regulation of epithelial sodium channel abundance in rat kidney.
Sodium transport is increased by vasopressin in the cortical collecting ducts of rats and rabbits. Here we investigate, by quantitative immunoblotting, the effects of vasopressin on abundances of the epithelial sodium channel (ENaC) subunits (alpha, beta, and gamma) in rat kidney. Seven-day infusion of 1-deamino-[8-D-arginine]-vasopressin (dDAVP) to Brattleboro rats markedly increased whole kidney abundances of beta- and gamma-ENaC (to 238% and 288% of vehicle, respectively), whereas alpha-ENaC was more modestly, yet significantly, increased (to 142% of vehicle). Similarly, 7-day water restriction in Sprague-Dawley rats resulted in significantly increased abundances of beta- and gamma- but no significant change in alpha-ENaC. Acute administration of dDAVP (2 nmol) to Brattleboro rats resulted in modest, but significant, increases in abundance for all ENaC subunits, within 1 h. In conclusion, all three subunits of ENaC are upregulated by vasopressin with temporal and regional differences. These changes are too slow to play a major role in the short-term action of vasopressin to stimulate sodium reabsorption in the collecting duct. Long-term increases in ENaC abundance should add to the short-term regulatory mechanisms (undefined in this study) to enhance sodium transport in the renal collecting duct.
Ecelbarger
C A
CA
Division of Endocrinology, Georgetown University, Washington, District of Columbia 20007, USA. ecelbarc@gunet.georgetown.edu
Kim
G H
GH
Terris
J
J
Masilamani
S
S
Mitchell
C
C
Reyes
I
I
Verbalis
J G
JG
Knepper
M A
MA
D000818:Animals; D051399:Aquaporin 2; D051403:Aquaporin 6; D020346:Aquaporins / Q000378:metabolism; D001581:Benzothiadiazines; D002352:Carrier Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D003894:Deamino Arginine Vasopressin / Q000008:administration & dosage / Q000494:pharmacology*; D004232:Diuretics; D053503:Epithelial Sodium Channels; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism; D015151:Immunoblotting; D017136:Ion Transport / Q000187:drug effects; D007668:Kidney / Q000187:drug effects* / Q000378:metabolism; D007672:Kidney Cortex / Q000187:drug effects / Q000378:metabolism; D007685:Kidney Tubules, Collecting / Q000187:drug effects / Q000378:metabolism; D008297:Male; D011817:Rabbits; D051381:Rats; D011919:Rats, Inbred Strains; D011955:Receptors, Drug / Q000037:antagonists & inhibitors / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D015222:Sodium Channels / Q000378:metabolism*; D049993:Sodium Chloride Symporter Inhibitors / Q000494:pharmacology; D049992:Sodium Chloride Symporters; D064486:Solute Carrier Family 12, Member 3; D027981:Symporters; D015854:Up-Regulation / Q000187:drug effects; D014868:Water Deprivation
C496025:Aqp2 protein, rat; D051399:Aquaporin 2; D051403:Aquaporin 6; D020346:Aquaporins; D001581:Benzothiadiazines; D002352:Carrier Proteins; D004232:Diuretics; D053503:Epithelial Sodium Channels; D011955:Receptors, Drug; C578876:Slc12a3 protein, rat; D015222:Sodium Channels; D049993:Sodium Chloride Symporter Inhibitors; D049992:Sodium Chloride Symporters; D064486:Solute Carrier Family 12, Member 3; D027981:Symporters; C064415:thiazide receptor; D012964:Sodium; D003894:Deamino Arginine Vasopressin