UT-A1 ve UT-A3 üre taşıyıcıları, terminal iç medüller toplama kanalında (IMCD) eksprese edilir ve konsantre idrar üretiminde önemli bir rol oynar. Hem hiperozmolaritenin hem de vazopressinin perfüze edilmiş sıçan terminal IMCD’lerinde üre geçirgenliğini arttırdığını ve UT-A1 ve UT-A3’ün vazopressine yanıt olarak plazma zarında birikir.
Urea in the inner collecting duct (due to ADH regulation of UTA-1 and UTA-2 channels).
UT-A1
Urea transporter A1 transports urea across the apical membrane into the intracellular space of luminal cells in the inner medullary collecting duct of the kidneys. UT-1 is activated by ADH, but is a passive transporter. It reabsorbs up to 70% of the original filtered load of urea.
UT-A2
Urea Transporter 2 transports urea across the apical membrane into the luminal space of cells in the thin descending loop of Henle of the kidneys.
UT-A3
Urea transporter 3 transports urea into the interstitium of the Inner Medullary Collecting Duct.
UT-A4
Urea transporter 4 has been detected in rat but not mouse kidney medulla.
UT-A5
Urea transporter 5 is not expressed in the kidney but in the testis.
UT-B
UT-B is widely expressed and has been studied in erythrocytes, kidney, intestine, and at the blood–brain barrier. The SLC14A1 gene codes for the UT-B protein. UT-B is expressed at the basolateral and apical regions of the descending Vasa recta.
Aşağıdaki üre transportlarından hangileri antidiüretik hormona (ADH) en duyarlıdır? (UT: Üre transporteri)
A) UTA-1 ve UTA-2
B) UTA-2 ve UTA-3
C) UTA-1 ve UTA-3 ***********
D) UTA-1 ve UTB
E) UTA-3 ve UTB