Fig. 2.

Indirect immunofluorescence microscopy of NHE3 distribution in the proximal tubules of rats on 3-wk 0.4% NaCl (NS) or 4% NaCl (HS). The kidneys were fixed as described in methods. The antibody against NHE3 was polyclonal and detected with FITC-conjugated goat anti-rabbit secondary antibody, whereas the antibody against villin was monoclonal and detected with Alexa 568-conjugated goat anti-mouse secondary antibody. Surface sections were double-labeled against NHE3 (green) and villin (red). In rats fed 4% NaCl for 3 wk, NHE3 is retracted from the body of the microvilli to the base (green), revealing the villin staining in red. n = 3/group. Bar, 10 μm.