Diabetes insipidus (DI) is a condition caused by hyposecretion of, or insensitivity to the effects of, antidiuretic hormone (ADH), also known as arginine vasopressin (AVP). ADH is synthesised in the hypothalamus and transported as neurosecretory vesicles to the posterior pituitary. There it is released into the circulation, governed by plasma osmolality. Its deficiency or failure to act causes an inability to concentrate urine in the distal renal tubules, leading to the passage of copious volumes of dilute urine. Usually the person with this condition passes >3 litres/24 hours of low osmolality (<300 mOsmol/kg) urine.
This is a companion discussion topic for the original article at https://patient.info/doctor/diabetes-insipidus-pro