Posterior pituitary insufficiency leads to:
Diabetes mellitus
Diabetes insipidus
Dwarfism
Cretinism
ADH SYNTHESIS IN SUPRAOPTIC AND PARAVENTRICULAR NUCLEI OF THE HYPOTHALAMUS AND ADH RELEASE FROM THE POSTERIOR PITUITARY
Figure shows the neuroanatomy of the hypothalamus and the pituitary gland, where ADH is synthesized and released. The hypothalamus contains two types of magnocellular (large) neurons that synthesize ADH in the supraoptic and paraventricular nuclei of the hypothalamus, about five sixths in the supraoptic nuclei and about one sixth in the paraventricular nuclei. Both of these nuclei have axonal extensions to the posterior pituitary.
The most important renal action of ADH is to increase the water permeability  of  the  distal  tubule,  collecting  tubule, and collecting duct epithelia. This effect helps the body to conserve water in circumstances such as dehydration. In the absence of ADH, the permeability of the distal tubules and collecting ducts to water is low, causing the kidneys to excrete large amounts of dilute urine, a condition called diabetes insipidus. Thus, the actions of ADH play a key role in controlling the degree of dilution or concentration of the urine.