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Urea flux across MDCK‐mUT‐A2 monolayers is acutely sensitive to AVP, cAMP and [Ca2+]I
Author(s) -
Smith Craig P,
Stewart Gavin,
Potter Elizabeth A
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a1219
Subject(s) - phloretin , urea , forskolin , chemistry , biophysics , monolayer , intracellular , flux (metallurgy) , medicine , endocrinology , biochemistry , in vitro , biology , organic chemistry
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 10μM forskolin or 250μM 8‐bromo cAMP also increased urea flux rate. Inclusion of the PKA inhibitor H89 (10μM), had no effect on the forskolin‐stimulated increase in urea flux across MDCK‐mUT‐A2 monolayers. Treatment with either 10μM 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.