Nocturia, or nocturnal polyuria, is a medical term which means excessive urination at night. The two primary causes of nocturia are hormone imbalance and vesicle problems. Arginine vasopressin (AVP) and atrial natriuretic hormone (ANH) are two of the hormones that controls the body water level. AVP is an antidiuretic hormone produced by hypothalamus while ANH is released by cardiac muscle cells in response to high blood pressure. Arginine vasopressin (AVP) is an antidiuretic hormone which increases water absorption in the collecting duct systems of of kidney nephrons subsequently decreasing urine production. In the abovementioned question, nocturia is caused by decreased production of antidiuretic hormone, which is the arginine vasopressin. Nocturia, moreover, is can be caused by congestive heart disease, nephritic syndrome or liver failure. Excessive nighttime drinking and obstructive apnea can also lead to nocturia