Physiological functions of urea transporter B

Abstract

Urea transporters (UTs) are membrane proteins in the urea transporter protein A (UT-A) and urea transporter protein B (UT-B) families. UT-B is mainly expressed in endothelial cell membrane of the renal medulla and in other tissues, including the brain, heart, pancreas, colon, bladder, bone marrow, and cochlea. UT-B is responsible for the maintenance of urea concentration, male reproductive function, blood pressure, bone metabolism, and brain astrocyte and cardiac functions. Its deficiency and dysfunction contribute to the pathogenesis of many diseases. Actually, UT-B deficiency increases the sensitivity of bladder epithelial cells to apoptosis triggers in mice and UT-B-null mice develop II-III atrioventricular block and depression. The expression of UT-B in the rumen of cow and sheep may participate in digestive function. However, there is no systemic review to discuss the UT-B functions. Here, we update research approaches to understanding the functions of UT-B.

Kinetic modelling of dissolution dynamic nuclear polarisation 13C magnetic resonance spectroscopy data for analysis of pyruvate delivery and fate in tumours

“…Nevertheless, it is often described as freely diffusible through lipid bilayers, its transport being facilitated by molecular transporters. UT‐B urea transporters are found in many nonrenal cells and all endothelial cells studied so far, including capillary endothelial cells 34,35 . Although some authors have assumed that intravenously administered urea remains in the vasculature of tumours, at least for the short observation period available for dDNP, 32 others have shown it readily entering the interstitium 36 .…”

“…UT-B urea transporters are found in many nonrenal cells and all endothelial cells studied so far, including capillary endothelial cells. 34,35 Although some authors have assumed that intravenously administered urea remains in the vasculature of tumours, at least for the short observation period available for dDNP, 32 others have shown it readily entering the interstitium. 36 In a dDNP study, the apparent diffusion coefficient for 13 C-urea was estimated to be very similar to that of water, also implying rapid clearance of urea from the blood to the interstitium.…”

Neuroglia Cells Transcriptomic in Brain Development, Aging and Neurodegenerative Diseases

“…However, an increase in aminoacids metabolism will result in an increased nitrogen concentration in neurons that has to be removed as urea. Slc14a1 is a gene encoding a urea membrane transporter in astrocytes that is co-expressed with the astrocytic marker GFAP and is important for the removal of urea from the CNS [24]. Moreover, enhanced expression of the Slc14a1 gene has been reported in conditions favouring urea accumulation in neurodegenerative diseases, including Alzheimer's and Huntington's disease [25][26][27].…”

The potential role of antibodies against minor blood group antigens in renal transplantation

“…The urea transporter is highly conserved between species but mRNA for this human gene (hUT-B1) is found in a number of organs and is identical to the Kidd gene but for a base pair substitution and a deletion [28]. The fact that this is a persistent gene through species speaks to its value, so it is interesting that a null-mutant urea transporter is not phenotypically more obvious [29].…”