What are the types of cells present in coical collecting duct?

Both Principal (P) cells & Intercalated (I) cells.Cells involved in reabsorption in coical collecting duct:Principal (P) cells.Intercalated (I) cells.FUNCTIONS OF 'P' CELLS:1. Sodium & water reabsorption:Reabsorbed from lumen.Occurs through Na2+ channels (ENaC channels). Approximately 3% Na reabsorption occurs.2. Potassium secretion:Secreted into lumen.K+ both secreted & reabsorbed.Note: Na2+ reabsorption & K+ secretion depends on,Na2+-K+-ATPase activity in basolateral membrane.Aldosterone.3. Water reabsorption:ADH Controlled.Stimulates water channel, aquaporin-2.FUNCTIONS OF 'I' CELLS:Reabsorb potassium ion.Secrete hydrogen ions into tubular lumen.