The pituitary gland is an important part of the hormonal system. It makes many different hormones. Some of these hormones have direct effects on the body, and others control the actions of other glands that produce hormones.
What is the pituitary gland?
The pituitary gland sits in a pocket of the skull under the middle part of the brain. It is quite small — about the size of a pea.
The pituitary is controlled in two ways: by signals from the part of the brain called the hypothalamus, and by sensing levels of other hormones in the body.
What hormones does the pituitary gland make?
The pituitary gland makes:
- growth hormone, which regulates growth
- thyroid stimulating hormone, which tells the thyroid gland to make thyroid hormones
- prolactin, which controls breast milk production
- hormones involved in the reproductive cycle
- a hormone that helps control the adrenal glands
- oxytocin, which is involved in childbirth and breastfeeding
- antidiuretic hormone, which helps control how much fluid is in your body
Medical conditions related to the pituitary gland
The pituitary gland can become disturbed and make too much or too little of a hormone. It can also be the site of a tumour, which can cause problems by squashing the surrounding brain tissue. Most tumours in the pituitary gland are benign and only cause problems when they change hormone levels or take up too much space.
Here are some of the more common pituitary conditions.
- Hyperprolactinaemia (too much prolactin) — a woman with hyperprolactinaemia might notice her periods becoming lighter or stopping, might have difficulty getting pregnant and can also lead to lactating (producing breast milk).
- Growth hormone deficiency — this can delay children’s growth and lead to a child being shorter in height than expected. In adults, growth hormone deficiency can cause fatigue, weak muscles, excess weight and can affect bone health.
- Hypopituitarism — this is a deficiency of all the pituitary hormones and causes many different symptoms.
Rare pituitary conditions include:
- gigantism — where a person grows very tall
- acromegaly — where a person’s hands, feet and jaw enlarge
- Cushing’s syndrome — where the body creates too many steroid hormones
Last reviewed: November 2018