Walpole, CaraghCaraghWalpoleMcGrane, AlisonAlisonMcGraneAl-mousawi, HashemeyaHashemeyaAl-mousawiWinter, Desmond C.Desmond C.WinterBaird, Alan W.Alan W.BairdStewart, GavinGavinStewart2019-04-242019-04-242018 the A2018-08-12Physiological Reports2051-817Xhttp://hdl.handle.net/10197/10116The symbiotic relationship between humans and their intestinal microbiomeis supported by urea nitrogen salvaging. Previous studies have shown thatcolonic UT-B urea transporters play a significant role in this important physi-ological process. This current study investigated UT-A and UT-B urea trans-porter expression along the human gastrointestinal tract. Initial end-pointPCR experiments determined that UT-A RNA was predominantly expressedin the small intestine, while UT-B RNA was expressed in stomach, small intes-tine, and colon. Using western blotting experiments, a strong 40–60 kDa UT-B signal was found to be abundant in both ileum and colon. Importantly, thissignal was deglycosylated by PNGaseF enzyme treatment to a core protein of30 kDa in both tissues. Further immunolocalization studies revealed UT-Btransporter proteins were present at the apical membrane of the villi in theileum, but predominantly at the basolateral membrane of the colonic surfaceepithelial cells. Finally, a blind scoring immunolocalization study suggestedthat there was no significant difference in UT-B abundance throughout thecolon (NS, ANOVA,N=5–21). In conclusion, this current study suggestedUT-B to be the main human intestinal urea transporter. Intriguingly, thesedata suggested that the same UT-B isoform was present in all intestinalepithelial cells, but that the precise cellular location varied.enPhysiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.Gastrointestinal tractHumanUT‐AUT‐BJournal Article615e1382610.14814/phy2.138262018-08-1511/RFP.1/BMT/3088https://creativecommons.org/licenses/by-nc-nd/3.0/ie/