absorb Na and water

secrete K into lumen

Na/K ATPase pump in basolateral membrane

site of action for:

• Aldosterone
• K sparing diuretics (i.e. they ↓ K excretion into urine)
  • spironolactone (since, as a mineralocorticoid receptor antagonist, it competes with aldosterone)
  • amiloride (directly inhibit Na entry)