Pituitary Gland

The pituitary is a pea-sized gland that is located within a bony structure at the base of the brain. The bony structure sella turcica protects the pituitary but allows very little space for expansion. It is also called master gland as pituitary controls the function of most other endocrine glands. It detects the level of hormones produced by glands and determines how much stimulation is needed. The pituitary has two distinct parts the front lobe, which has about 80% of the pituitary gland's weight, and the back lobe.

Function of anterior lobe of pituitary gland: The front lobe (anterior lobe) of the pituitary produces and secretes six main hormones.

1.       Growth hormone, which regulates or controls growth and physical development and is very important for body shape as it stimulate the muscle formation and helpful in reducing fat tissue.

2.       Thyroid-stimulating hormone: As indicated by name, it stimulates the thyroid gland to produce thyroid hormones.

3.       Adrenocorticotropic hormone: It stimulates the adrenal glands to produce cortical and other hormones.

4.       Follicle-stimulating hormone and luteinizing hormone: The function of these hormones is to stimulate the testes to produce sperm, the ovaries to produce eggs, and the sex organs to produce sex hormones.

5.       Prolactin: This hormone is responsible to stimulate the mammary glands of the breasts to produce milk in case of females.

6.       Beta-melanocyte stimulating hormone is responsible skin to darken and inhibit pain sensations to control immune system.

Function of back lobe of pituitary gland: The back lobe or posterior lobe of the pituitary produces antidiuretic hormone and oxytocin. Antidiuretic hormone regulates the amount of water excreted by the kidneys and is thus important for maintaining water balance in the body. Oxytocin helps the uterus to contract during childbirth and immediately after delivery to prevent excessive bleeding and also stimulates contractions of the milk ducts in the breast.

Diagnosing of pituitary gland problems: There are several tests available to diagnose pituitary gland malfunction. CT scan or MRI scans show whether the pituitary has enlarged or shrunk. Such tests possibly determine whether a tumor exists in the gland. Simple blood test can measure the levels of pituitary hormones. Doctors select which pituitary hormone levels they want to measure which further depends on the person's symptoms. Sometimes pituitary hormones levels are not easy to interpret because they vary greatly during the day and according to the body's needs. For measuring these hormones a random blood sample does not provide complete information. For example, if a doctor injects insulin, the levels of ACTH, growth hormone, and Prolactin should increase. Instead of  measuring growth hormone levels directly, doctors often measure another hormone, insulin-like growth factor 1 (IGF-1). Growth hormone is produced in bursts and its levels quickly fall, but IGF-1 levels reflect the overall daily production of growth hormone.