The pituitary is an endocrine (hormone-producing) gland that sits just beneath the base of the brain, behind the bridge of the nose. It is very small – only about the size of a pea. The pituitary gland is very important as it takes messages from the brain (via a gland called the hypothalamus) and uses these messages to produce hormones that affect many parts of the body, including stimulating all the other hormone-producing glands to produce their own hormones. For this reason it is often referred to as the ‘master gland’.

The pituitary gland is divided into two parts. The anterior (or front lobe) pituitary produces hormones that affect the breasts, adrenals, thyroid, ovaries and testes, as well as several other organs. The main organ affected by the posterior (or rear lobe) pituitary is the kidneys.

The anterior lobe secretes six major hormones:

Growth hormone (GH),
- regulates growth and development

Thyroid-stimulating hormone (TSH),
- stimulates the thyroid gland to make thyroid hormones

Adrenocorticotropic hormone (ACTH),
- stimulates the adrenal glands to make cortisol and other hormones

Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) (the gonadotropins),
-  regulates the menstrual cycle in women, sperm production in men, and sex hormone levels in both sexes (testosterone and estrogen)

Prolactin (PRL),
- stimulates the mammary glands of the breasts to produce milk after giving birth

The posterior lobe of the pituitary makes two primary hormones:

ADH (antidiuretic hormone),                                                                                          
- helps the kidneys to maintain the correct amount of water in the body

Oxytocin,                                                                                                                         
- causes the uterus to contract throughout childbirth and stimulates milk production