Introduction: The pituitary is a small gland inside the head, behind the bridge of the nose. Though small, it produces many important hormones that regulate basic body functions. The major pituitary hormones and their effects are:

• prolactin--controls formation of breast milk, influences fertility, and influences bone strength;

• growth hormone--regulates body growth, especially during adolescence;

   

• adrenocorticotropin (ACTH)--stimulates the adrenal glands to produce cortisol;

   

• thyrotropin (TSH)--stimulates the thyroid gland to produce thyroid hormones;

   

• luteinizing hormone (LH)--stimulates the ovaries or testes to produce sex hormones that determine many features of "maleness" or "femaleness"; and

• follicle stimulating hormone (FSH)--regulates fertility in men through sperm production and in women through ovulation.

The pituitary gland, sometimes called the master gland, plays a critical role in regulating growth and development, metabolism, and reproduction. It produces prolactin and a variety of other key hormones. These include growth hormone, which regulates growth; ACTH (corticotropin), which stimulates the adrenal glands to produce cortisol; thyrotropin, which signals the thyroid gland to produce thyroid hormone; and luteinizing hormone and follicle-stimulating hormone, which regulate ovulation and estrogen and progesterone production in women, and sperm formation and testosterone production in men.

The pituitary gland sits in the middle of the head in a bony box called the sella turcica. The eye nerves sit directly above the pituitary gland. Enlargement of the gland can cause local symptoms such as headaches or visual disturbances. Pituitary tumors may also impair production of one or more pituitary hormones, causing reduced pituitary function (hypopituitarism). ³