The electrochemical gradient for K+ across the luminal membrane of the proximal tubule
favors K+ fluxes to the lumen. Here it was demonstrated by immunohistochemistry that
KCNE1 and KCNQ1, which form together the slowly activated component of the delayed
rectifying K+ current in the heart, also colocalize in the luminal membrane of proximal tubule
in mouse kidney. Micropuncture experiments revealed a reduced K+ concentration in late
proximal and early distal tubular fluid as well as a reduced K+ delivery to these sites in …