What are the major functions of "I" cells?

Reabsorb potassium ion.REABSORPTION IN LATE DISTAL TUBULE:Functionally similar to coical collecting tubule.Facultative type:Reabsorption of solutes/water depends on water/electrolyte balance.Hence, "Facultative type" of absorption.Cells involved in reabsopion:Principal (P) cells.Intercalated (I) cells.FUNCTIONS OF 'I' CELLS:Reabsorb potassium ion.Secrete hydrogen ions into tubular lumen.