Urea transporters in kidney: molecular analysis and contribution to
the urinary concentrating process.
Tsukaguchi, Hiroyasu, Chairat Shayakul, Urs V. Berger, and Matthias A.
Hediger.
Renal Division, Department of Medicine, Brigham and Women's
Hospital, Harvard Medical School, Boston, MA 02115.
APStracts 5:0101F, 1998.
Facilitated urea transporters (UTs) are responsible for urea
accumulation in the renal inner medulla of the mammalian kidney and
therefore play a central role in the urinary concentrating process.
Recently, the cDNAs encoding three members of the UT family, UT1,
UT2, and UT3 have been cloned. These transporters are expressed in
different structures of the mammalian kidney. In rat, UT1 resides in
the apical membrane of terminal inner medullary collecting ducts
where it mediates vasopressin-regulated urea reabsorption. UT2 and
UT3 are located in descending thin limbs of Henle's loop and
descending vasa recta, respectively, and participate in urinary
recycling processes which minimize urea escape from the inner
medulla. UT1 and UT2 are regulated independently and respond
differently to changes in dietary protein content and hydration
state. Identification and characterization of these urea transporters
advances our understanding of the molecular basis and regulation of
the urinary concentrating mechanism.
Received 13 May 1998; accepted in final form 13 May 19980.
APS Manuscript Number F120-8.
Article publication pending Am. J. Physiol. (Renal Physiology).
ISSN 1080-4757 Copyright 1998 The American Physiological Society.
Published in APStracts on 16 June 1998