Urea transporter A1 (UT-A1)

Urea transporter A1 (UT-A1) is a membrane protein encoded by the SLC14A2 gene, predominantly expressed in the apical membrane of the inner medullary collecting duct of the kidney[2][5][6]. UT-A1 facilitates the passive, selective transport of urea across cell membranes, playing a central role in renal urea reabsorption and the urine-concentrating mechanism[2][7]. It enables the kidney to concentrate urine and conserve water during states of dehydration[2][5]. The activity of UT-A1 is regulated by vasopressin, which increases its phosphorylation and membrane expression[4][7]. Genetically or pharmacologically targeting UT-A1 leads to an increase in urine output and a decrease in urine osmolality, presenting a promising diuretic strategy that typically spares electrolyte loss compared to conventional diuretics[2][6]. While there are no clinically approved UT-A1–specific inhibitors as of August 2025, experimental compounds and urea analogues can inhibit UT-A1-mediated transport[5]. Dysfunction or genetic deletion of UT-A1 can result in water balance disorders such as nephrogenic diabetes insipidus[2].

Other names

Urea transporter 1SLC14A2 (gene name)UT1

Inhibitors block passive urea transport across the apical membrane of inner medullary collecting duct cells, impairing renal urea reabsorption and causing diuresis