The Pituitary Gland

The pituitary gland is one of the body’s endocrine glands. It is sometimes called the “master gland,” because it controls the functions of other endocrine glands.

Endocrine glands release chemical messengers (hormones) into the bloodstream to be carried to organs and tissues throughout the body.

The pituitary is located at the base of the brain. It is small and is divided into three parts: anterior lobe, intermediate lobe, and posterior lobe. The anterior lobe is largest, making up about 80 percent of the gland.

The anterior lobe produces the following hormones:

• Growth hormone, which affects many other glands       

• Prolactin, which stimulates milk production in women after giving birth

• Adrenocorticotropic hormone, which stimulates the adrenal glands

• Thyroid-stimulating hormone, which stimulates the thyroid gland

• Luteinizing hormone, which stimulates the ovaries or testes

• Follicle-stimulating hormone, which stimulates ovaries or testes

The intermediate lobe produces melanocyte, a hormone that controls skin pigmentation.

The posterior lobe of the pituitary stores and releases an antidiuretic hormone that increases the absorption of water by the kidneys. This lobe also stores and releases oxytocin, a hormone that causes the uterus to contract, helps to slow blood flow during the birthing process and causes milk to flow when a woman breast-feeds.

The pituitary is intimately involved in growth, development, maintenance, and reproduction. The pituitary supplies growth hormone, which is responsible for growth from before birth to the end of growth at the end of puberty. The pituitary determines the timing for the onset of puberty and the cycling of the female menstrual cycle. It regulates the production of thyroid hormones that govern the overall metabolism of the body. It also controls the production of corticosteroids, which help govern such functions as electrolyte maintenance, blood pressure, inflammatory response, and response to stress.