What happens when the pituitary stops functioning normally? 

If the Negative feedback mechanism does not function effectively or the pituitary is impaired to the point where it can no longer produce specific hormones, this can have a range of effects on the body.

Changes in hormone production

There are various reason why the production of pituitary hormones increase or decrease, however these are often easily treated. These two different types of changes in hormone levels are explained:

 Underproduction of pituitary hormones

Overproduction of pituitary hormones 

 Tumour

The most common problem which can occur with pituitary function is when a Benign tumour develops on the pituitary. This is called an adenoma.

These tumours can often exist for many years without causing any symptoms. There appears to be no genetic link with the incidence of these cancers. The physical occurance of the tumour can cause problems in particular instances where it presses on the optic nerve causing problems with your eye sight. This is often also an intial symptom. 

"Non-functioning" tumour

This is the most common form of tumour (over half of known cases) and it is called non-functioning because the tumour does not secrete any hormones itself which can lead to a clinical syndrome. 

 Another example of a non-functioning tumour is a Craniopharyngioma. This is a congenital tumour which exerts pressure on the hypothalamus and sometimes also the pituitary. Fast growing ones have a more significant impact on children where as more slower growing ones affect adults.

Treatment

Initially, the tumours are merely obsevered by regular MRI scans as in many people they do not impead on their health. Once a tumour has been deamed to be of a dangerous size, neurosurgery is the primary route. This is also sometimes combined with radiation therapy.

"Functioning" tumour

This type of tumour produces hormones itself e.g Acromegaly  

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