The kidneys play pivotal roles in acid-base homeostasis, and the acid-secreting (α-type) and
bicarbonate-secreting (β-type) intercalated cells in the collecting ducts are major sites for the
final modulation of urinary acid secretion. Since the H+-ATPase and anion exchanger
activities in these two types of intercalated cells exhibit opposite polarities, it has been
suggested that the α-and β-intercalated cells are interchangeable via a cell polarity change.
Immunohistological studies, however, have failed to confirm that the apical anion exchanger …