TY - JOUR
T1 - Regulated expression of renal and intestinal UT-B urea transporter in response to varying urea load
AU - Inoue, Hideki
AU - Kozlowski, Shelley D.
AU - Klein, Janet D.
AU - Bailey, James L.
AU - Sands, Jeff M.
AU - Bagnasco, Serena M.
PY - 2005/8
Y1 - 2005/8
N2 - Production, recycling, and elimination of urea are important to maintain nitrogen balance. Adaptation to varying loads of urea due to different protein intake or in renal failure may involve changes in urea transport and may possibly affect urea transporters. In this study, we examined the expression of the UT-B urea transporter in rats fed a low-protein diet (LPD), a high-protein diet (HPD), and a 20% urea-supplemented diet. In the kidney, UT-B protein abundance increased in the outer medulla of both LPD-fed rats and 20% urea-fed rats, without changes in the inner medulla of either group compared with controls. In HPD-fed rats, UT-B protein decreased significantly in both the outer and inner medulla. We identified expression of UT-B in the rat colon, as a 2-kb mRNA transcript and as an ∼45-kDa protein, with apical localization in superficial colon epithelial cells. UT-B also is expressed in rat small intestine. In rat colon, UT-B protein abundance was mildly, but significantly, decreased in LPD-fed and 20% urea-fed rats. UT-B abundance also was examined in the colon of 7/8 nephrectomized, uremic rats and in HPD-fed rats and was not significantly different from that in control rats. These findings indicate that UT-B expression is regulated in response to different loads of urea, with a pattern that suggests involvement of tissue-specific regulatory mechanism in kidney and colon. Copyright ̀ 2005 the American Physiological Society.
AB - Production, recycling, and elimination of urea are important to maintain nitrogen balance. Adaptation to varying loads of urea due to different protein intake or in renal failure may involve changes in urea transport and may possibly affect urea transporters. In this study, we examined the expression of the UT-B urea transporter in rats fed a low-protein diet (LPD), a high-protein diet (HPD), and a 20% urea-supplemented diet. In the kidney, UT-B protein abundance increased in the outer medulla of both LPD-fed rats and 20% urea-fed rats, without changes in the inner medulla of either group compared with controls. In HPD-fed rats, UT-B protein decreased significantly in both the outer and inner medulla. We identified expression of UT-B in the rat colon, as a 2-kb mRNA transcript and as an ∼45-kDa protein, with apical localization in superficial colon epithelial cells. UT-B also is expressed in rat small intestine. In rat colon, UT-B protein abundance was mildly, but significantly, decreased in LPD-fed and 20% urea-fed rats. UT-B abundance also was examined in the colon of 7/8 nephrectomized, uremic rats and in HPD-fed rats and was not significantly different from that in control rats. These findings indicate that UT-B expression is regulated in response to different loads of urea, with a pattern that suggests involvement of tissue-specific regulatory mechanism in kidney and colon. Copyright ̀ 2005 the American Physiological Society.
KW - Colon
KW - Kidney
KW - Urea transport
KW - Uremia
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U2 - 10.1152/ajprenal.00376.2004
DO - 10.1152/ajprenal.00376.2004
M3 - Article
C2 - 15798087
AN - SCOPUS:22344454766
SN - 0363-6127
VL - 289
SP - F451-F458
JO - American Journal of Physiology - Renal Physiology
JF - American Journal of Physiology - Renal Physiology
IS - 2 58-2
ER -