Enuresis is the result of multifactorial processes. Enuretic patients often exhibit an abnormal diurnal rhythm of plasma vasopressin in addition to high nocturnal urine production. Renal function is considered to be a core factor in influencing the volume of fluid delivered to the bladder. Animal studies have suggested that the amount of fluid delivered to the bladder is dependent upon the state of hydration and/or the amount of protein present in the animal's diet. The state of hydration, or diuresis, may also influence the permeability of the terminal collecting ducts to water and urea and the hydro-osmotic response of the kidney to desmopressin. Multiple agents, including vasopressin, glucagon, calcitonin, parathyroid hormone, beta-adrenergic agonist, insulin, angiotensin II, prostaglandins and calcium and magnesium ions influence sodium transport in the thick ascending limb, indicating that all of these factors may potentially play a role in enuresis.