Figure 4.

Localization of pendrin relative to other proteins in human kidney. Paraformaldehyde-fixed, paraffin-embedded human kidney sections were double-labeled with a polyclonal antibody to aquaporin-2 (green; 1:1000) and a monoclonal antibody to pendrin (red; 1:50), with the staining seen in the CCDs shown in A. In B, similar sections were stained with a polyclonal antibody to H⁺-ATPase (green; 1:1000) and the anti-pendrin monoclonal antibody (red; 1:50). In the merged image, note the α-intercalated cell with apical staining for H⁺-ATPase (arrowhead) and the two other intercalated cells staining for both H⁺-ATPase and pendrin (arrows), with the resulting yellow areas corresponding to the pendrin-containing apical regions. Also note the other cells in the same tubule that are negative for both proteins; these are the principal cells. (Original magnification ×1000.)