Expression, localization, and regulation of urea transporter B in rat urothelia

David A. Spector, Qing Yang, Jie Liu, James B. Wade

Research output: Contribution to journalArticle

Abstract

Although mammalian urothelia are generally considered impermeable to urinary constituents, in vivo studies in several species suggest urothelial transport of water, urea, and solutes under certain conditions. This study investigates the expression, localization, and regulation of urea transporter-B (UT-B) in rat renal pelvis, ureter, and bladder tissues. Immunoblots of homogenates of tissues identified characteristic ∼40- to 55- and ∼32-kDa bands in the ureter, bladder, and renal inner medulla, but not renal cortex. UT-B was localized by immunocytochemistry and was strongly expressed in all cell membranes (and to a limited extent in intracellular vesicles in the cytoplasm) of epithelial cells lining the rat bladder, ureter, and renal pelvis lumens except the apical membrane of the umbrella cells. It was also present in single-layer papillary surface epithelial cells. There was no difference in immunoblot expression of UT-B in the bladder or ureteral homogenates between groups of rats fed high- or low-protein or high- or low-sodium diets. Water restriction resulted in an increase in UT-B expression in ureters (49%, P = 0.001) but not in bladders (14%, P = not significant). The functional role of UT-B in the genitourinary tract epithelia is unknown. UT-B may participate in the regulation of epithelial cell volume and osmolality, in the dissipation of urea gradients, and in possible net urea transport across uroepithelia.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Renal Physiology
Volume287
Issue number1 56-1
DOIs
StatePublished - Jul 2004

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Urothelium
Ureter
Urinary Bladder
Urea
Kidney Pelvis
Epithelial Cells
Cell Membrane
Kidney
Sodium-Restricted Diet
Water
Cell Size
Osmolar Concentration
urea transporter
Cytoplasm
Proteins
Epithelium
Sodium
Immunohistochemistry

Keywords

  • Immunocytochemistry
  • Urea transport
  • Western blot analysis

ASJC Scopus subject areas

  • Physiology

Cite this

Expression, localization, and regulation of urea transporter B in rat urothelia. / Spector, David A.; Yang, Qing; Liu, Jie; Wade, James B.

In: American Journal of Physiology - Renal Physiology, Vol. 287, No. 1 56-1, 07.2004.

Research output: Contribution to journalArticle

Spector, David A. ; Yang, Qing ; Liu, Jie ; Wade, James B. / Expression, localization, and regulation of urea transporter B in rat urothelia. In: American Journal of Physiology - Renal Physiology. 2004 ; Vol. 287, No. 1 56-1.
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