Posterior pituitary disorders

The posterior (back) lobe of the pituitary gland releases ADH (antidiuretic hormone) and oxytocin (a hormone to contract the uterus during childbirth and stimulate milk production). Antidiuretic hormone (ADH), which is also called vasopressin, helps the kidneys (and body) hold on to the appropriate amount water. For example, when a person becomes dehydrated, more ADH is produced to help the body conserve the water it contains. Inadequate ADH leads to excessive losses of water through urination. This can result in dangerous dehydration, high sodium levels, and increased thirst. This is a condition known as diabetes insipidus or DI. Too much ADH leads to excessive retention of water by the body and low sodium levels (syndrome of inappropriate antidiuretic hormone secretion or SIADH).