How renal cells handle urea

被引:15
作者
Bagnasco, SM [1 ]
机构
[1] Emory Univ, Sch Med, Dept Pathol, Atlanta, GA 30322 USA
关键词
kidney; urea; osmolytes; transporter; hypertonicity; vasopressin;
D O I
10.1159/000016377
中图分类号
Q2 [细胞生物学];
学科分类号
071009 ; 090102 ;
摘要
The urine concentration process requires an osmolality gradient along the renal cortico-medullary axis, with highest values in the renal papilla, NaCl and urea are the major solutes in the renal inner medulla, concentrations of urea up to 500-600 mM are found in the rat renal papilla. Urea can diffuse across cell membranes and contributes to balance intracellular and extracellular osmotic equilibrium. However, urea has perturbing effects on enzyme activity, and in concentrations above 300 mM is toxic for renal cultured cells. There is increasing evidence that urea can induce cellular responses distinct from those due to NaCl and other non-permeable solutes, including upregulation of immediate-early genes (IEGs). Urea transport by epithelial and endothelial cells is important for intra-medullary urea recycling and preservation of high urea concentration in the inner medulla, Transcellular movement of urea in cells expressing urea transporters may influence intracellular levels of this solute and modulate urea-induced signaling pathways. Regulation of urea transporters expression and activity can therefore be viewed as one aspect of cellular adaptation to urea. We have identified tonicity-responsive transcription as one mechanism regulating expression of the urea transporter UT-A. The shortterm and long-term effects of variable extracellular urea concentration on the function of renal cells remain still unclear. Copyright (C) 2000 S. Karger AG. Basel.
引用
收藏
页码:379 / 384
页数:6
相关论文
共 43 条
[1]  
BAGNASCO S, 1986, J BIOL CHEM, V261, P5872
[2]  
BAGNASCO SM, 2000, IN PRESS J AM SOC NE, P11
[3]  
Bankir L., 1996, KIDNEY, P571
[4]   Urea and methylamines have similar effects on aldose reductase activity [J].
Burg, MB ;
Peters, EM .
AMERICAN JOURNAL OF PHYSIOLOGY-RENAL PHYSIOLOGY, 1997, 273 (06) :F1048-F1053
[5]   Factors affecting counteraction by methylamines of urea effects on aldose reductase [J].
Burg, MB ;
Peters, EM ;
Bohren, KM ;
Gabbay, KH .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 1999, 96 (11) :6517-6522
[6]   UREA SELECTIVELY INDUCES DNA-SYNTHESIS IN RENAL EPITHELIAL-CELLS [J].
COHEN, DM ;
GULLANS, SR .
AMERICAN JOURNAL OF PHYSIOLOGY, 1993, 264 (04) :F601-F607
[7]  
COHEN DM, 1994, J BIOL CHEM, V269, P25865
[8]   UREA INDUCES EGR-1 AND C-FOS EXPRESSION IN RENAL EPITHELIAL-CELLS [J].
COHEN, DM ;
GULLANS, SR .
AMERICAN JOURNAL OF PHYSIOLOGY, 1993, 264 (04) :F593-F600
[9]   Protection of renal inner medullary epithelial cells from apoptosis by hypertonic stress-induced p53 activation [J].
Dmitrieva, N ;
Kültz, D ;
Michea, L ;
Ferraris, J ;
Burg, M .
JOURNAL OF BIOLOGICAL CHEMISTRY, 2000, 275 (24) :18243-18247
[10]   CLONING, GENOMIC ORGANIZATION, AND OSMOTIC RESPONSE OF THE ALDOSE REDUCTASE GENE [J].
FERRARIS, JD ;
WILLIAMS, CK ;
MARTIN, BM ;
BURG, MB ;
GARCIAPEREZ, A .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 1994, 91 (22) :10742-10746