KCNJ1 and Polyuria: The principal cell-specific K+ transporter, ROMK, was down-regulated (− 1.39-fold), while the BK alpha sub-unit (Kcnma1), a K+ large conductance Ca2+-activated channel, which is activated by flow (i.e. polyuria) [24] was significantly up-regulated (2.65-fold), though neither BK beta subunits (Kcnmb1 or Kcnmb4) were altered significantly [19].