endocrine and metabolic disorders
ArginineVasopressin Deficiency (Central Diabetes Insipidus)
Pathophysiology ofArginineVasopressinDeficiency
 plays an important role in maintaining Overview of Disorders of Fluid Volume and vascular and cellular hydration. The main stimuli for Increased osmotic pressure of water in the body (sensed by osmoreceptors in the hypothalamus) Volume depletion (sensed by vascular baroreceptors) The posterior lobe of the pituitary is the primary site ofvasopressinstorage and release, butvasopressinis synthesized within the hypothalamus. Newly synthesized hormone can still be released into the circulation as long as the hypothalamic nuclei and part of the neurohypophyseal tract are intact. Only about 10% of neurosecretory neurons must remain intact to avoidargininevasopressindeficiency. The pathology ofargininevasopressindeficiency thus always involves the supraoptic and paraventricular nuclei of the hypothalamus or a major portion of the pituitary stalk. Arginine vasopressindeficiency may be Complete (absence ofvasopressin) Partial (insufficient amounts ofvasopressin) Argininevasopressindeficiency also may be Primary, in which there is a marked decrease in the hypothalamic nuclei of the neurohypophyseal system Secondary (acquired) 