The rift valley contains the Jordan River and the Dead Sea, which separates Jordan from Israel and the Palestinian Territories. Jordan has a 26 kilometres (16 mi) shoreline on the Gulf of Aqaba in the Red Sea, but is otherwise landlocked.
Antidiuretic hormone binds to receptors on cells in the collecting ducts of the kidney and promotes reabsorption of water back into the circulation. In the absense of antidiuretic hormone, the collecting ducts are virtually impermiable to water, and it flows out as urine.
Certain drugs can also interfere with kidney function enough to cause potassium retention, including certain blood pressure drugs and potassium-sparing diuretics. The latter encourage the excretion of sodium while retaining potassium in the body.