The pituitary gland in the brain is responsible for many hormones and pre-hormones which are vital for normal function of the human body.
These include ACTH (which leads to cortisol secretion from the adrenal glands), TSH (which leads to thyroid hormone secretion from the thyroid gland), Growth Hormone, Prolactin, and the Gonadotrophins (which lead to reproductive hormone production from the ovaries or testes).
In the disease state the pituitary gland can oversecrete one of more of the hormones, under secrete one or more of the hormones, or tumours can grow in the pituitary which can affect vision amongst other things. Endocrinologists are generally required to manage all of these problems and also help look after hospital patients who have had surgery on their pituitary gland to ensure they do not become unwell due to their hormone irregularities.