AVP and Central diabetes insipidus: Polyuria is also the characteristic feature of diabetes insipidus (both neurologic and nephrogenic), whereas chronic urinary free water excretion (from AVP suppression or renal insensitivity) is counterbalanced by osmotic thirst stimulation and concomitant water intake, which matches urinary fluid losses (to maintain plasma [Na+] within the normal physiological range) [21,47,83].