Fig. 5.

Aldosterone or activation of protein kinase C enhances luminal H⁺-ATPase. Immunofluorescence labeling for the A subunit of the V-ATPase (red) in control (A), 20 μM DOG- (B), and 200 nM aldosterone-treated (C) rat OMCD intercalated cells. The nuclei are identified by DAPI staining (blue). While intercalated cells from control animals (A) exhibit extensive cytoplasmic staining and their apical membranes have a smooth appearance, extensively stained apical microvilli are readily detectable in the treated rats, and the cytosolic domain staining is less intense. An increased response is seen in the inset of C, which shows an intercalated cell from a rat treated with a higher concentration of aldosterone (200 μM). Bar = 20 μm.