What is Pituitary Gland?
The pituitary gland is a small gland at the base of the brain, often called the "master gland" because it controls many other endocrine glands. It receives signals from the hypothalamus and releases hormones into the bloodstream.
Key Functions
- •Stress response — releases ACTH, which stimulates the adrenal glands to release cortisol
- •Growth — growth hormone
- •Reproduction — gonadotropins
- •Metabolism — thyroid-stimulating hormone
- •Fluid balance — antidiuretic hormone
In the HPA Axis
Hypothalamus → CRH → Pituitary → ACTH → Adrenal → Cortisol. The pituitary is the middle link in the stress response chain.
Why does the Pituitary Gland matter?
The pituitary gland matters because it controls many of the body's other hormone glands, including the thyroid, adrenal glands, and ovaries or testes. For this reason it is often called the "master gland," though it takes its own orders from the hypothalamus.
Its hormones regulate growth, metabolism, stress responses, reproduction, and water balance. A small change in pituitary output can therefore have wide effects across the body.
What happens when the Pituitary Gland goes wrong?
When the pituitary gland goes wrong, the body may make too much or too little of one or more hormones. The most common cause is a pituitary adenoma, a usually noncancerous growth. Some adenomas release excess hormones, such as growth hormone, which causes acromegaly, or prolactin, which can affect fertility and menstrual cycles.
Larger growths can press on nearby structures, including the optic nerves, leading to headaches or loss of side vision. Reduced pituitary function, called hypopituitarism, can follow tumors, surgery, head injury, or bleeding, and may cause fatigue, low blood pressure, or reproductive problems. A lack of antidiuretic hormone causes diabetes insipidus, marked by heavy urination and thirst. These conditions are diagnosed with blood tests and imaging.