Urea flux across MDCK-mUT-A2 monolayers is acutely sensitive to AVP, cAMP and [Ca2+]i

Potter EA, Stewert G, Smith CP
Source: Am J Physiol Renal Physiol
Publication Date: (2006)
Issue: 291(1): F122-8
Research Area:
Cancer Research/Cell Biology
Cells used in publication:
Species: canine
Tissue Origin: kidney
Nucleofector® I/II/2b
In this study we engineered an MDCK type I cell line to stably express the mouse urea transporter UT-A2. Monolayers of MDCK-mUT-A2 cells had a basal phloretin-inhibitable urea permeability of 8.4x10(-6) +/- 0.3 cm/sec. Treatment of MDCK-mUT-A2 monolayers with AVP led to a rapid dose dependent increase in trans-monolayer phloretin-inhibitable urea flux. The temporal pattern of response was markedly different from that observed for MDCK cells expressing rat UT-A1. Exposure of MDCK-mUT-A2 cells to either 10microM forskolin or 250microM 8-bromo cAMP also increased urea flux rate. Inclusion of the PKA inhibitor H89 (10microM), had no effect on the forskolin-stimulated increase in urea flux across MDCK-mUT-A2 monolayers. Treatment with either 10microM CPA or 1mM ATP also caused an increase in UT-A2 mediated urea flux, although these responses where transient compared to those induced by AVP or elevated cAMP. Taken together these results show for the first time that UT-A2 is acutely sensitive to AVP, cAMP and increased intracellular calcium.