| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Laboratory of Kidney and Electrolyte Metabolism, National Heart, Lung and Blood Institutes, National Institutes of Health, Bethesda, MD, USA
2 University of Iowa and Veterans Affairs Medical Center, Department of Internal Medicine, Iowa City, Iowa, USA
* To whom correspondence should be addressed. E-mail: Fentonr{at}nhlbi.nih.gov.
Since abnormalities of inner medullary function have been proposed in Dahl salt-sensitive (DS) rats versus salt-resistant (DR) rats, we performed transporter profiling by semi-quantitative immunoblotting to determine if specific solute transporter abundances are altered in inner medullas of DS rats versus DR rats. Although none of the expressed Na transporters were up-regulated in the inner medullas of DS rats compared to DR rats, there were marked increases in the protein abundances of the collecting duct urea transporters; UT-A1 (to 212% of DR) and UT-A3 (to 223% of DR). These differences were confirmed by immunocytochemistry. Quantitative real-time PCR showed higher mRNA abundance in DS rats for both UT-A1 (to 256% of DR) and UT-A3 (to 210% of DR). In isolated, perfused IMCDs, urea permeability was significantly greater in DS rats. Since both UT-A1 and UT-A3 are transcriptionally regulated by glucocorticoids, we measured both plasma corticosterone levels and inner medullary 11
-hydroxysteroid dehydrogenase type 2 (11-HSD2) abundances. Although the plasma corticosterone concentrations were not different between DS and DR rats, immunoblotting and immunocytochemistry revealed a marked elevation of 11-HSD2 abundance in DS rats. Consistent with the view that an elevated 11-HSD2 level is responsible for increased urea transporter expression in the IMCD, administration of the 11-HSD2 inhibitor carbenoxolone to DS rats decreased the abundances of UT-A1 and UT-A3 to levels similar to those seen in DR rats.
This article has been cited by other articles:
|
|
 |
|
  R. A. Fenton and M. A. Knepper Urea and Renal Function in the 21st Century: Insights from Knockout Mice J. Am. Soc. Nephrol., March 1, 2007; 18(3): 679 - 688. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. A. Fenton, A. Shodeinde, and M. A. Knepper UT-A urea transporter promoter, UT-A{alpha}, targets principal cells of the renal inner medullary collecting duct Am J Physiol Renal Physiol, January 1, 2006; 290(1): F188 - F195. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. A. Fenton, C.-L. Chou, G. S. Stewart, C. P. Smith, and M. A. Knepper Urinary concentrating defect in mice with selective deletion of phloretin-sensitive urea transporters in the renal collecting duct PNAS, May 11, 2004; 101(19): 7469 - 7474. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. A. Gertner, J. D. Klein, J. L. Bailey, D.-u. Kim, X. H. Luo, S. M. Bagnasco, and J. M. Sands Aldosterone Decreases UT-A1 Urea Transporter Expression via the Mineralocorticoid Receptor J. Am. Soc. Nephrol., March 1, 2004; 15(3): 558 - 565. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |
