Small-molecule inhibitors of UT-A. a | The chemical structure of UTA inh-A1 and the chemical structure of UTAinh-E02. b | Concentration–inhibition data for UTAinh-A1 inhibition of UT-A1 and UT-B urea transport. UT-A1 inhibition exhibits an IC50 of 1–2 μM, approximately 100-fold higher than the IC50 it exhibits for UT-B inhibition. Abbreviations: inh, inhibitor; UT, urea transporter. Permission for part b obtained from the Federation of American Societies for Experimental Biology © Esteva-Font, C. et al. FASEB J. 28, 3878–3890 (2014).