Virginia Commonwealth University

VCU Massey Cancer Center

What are pituitary tumors?

The pituitary gland is a small, pea-sized organ in the brain behind the back of the nose. The pituitary gland produces hormones that affect many other glands in the body. Although rare, most pituitary tumors are noncancerous (benign), comprising only 10 percent of brain tumors. However, because of the location of the pituitary gland, at the base of the skull, a pituitary tumor grows upward. And, eventually, most pituitary tumors press against the optic nerves, causing vision problems.

Anatomy of the pituitary gland

The pituitary gland is sometimes called the “master” gland of the endocrine system, because it controls the functions of the other endocrine glands. The pituitary gland is no larger than a pea and is located at the base of the brain. The gland is attached to the hypothalamus (a part of the brain that affects the pituitary gland) by nerve fibers. The pituitary gland itself consists of three sections:

  • The anterior lobe
  • The intermediate lobe
  • The posterior lobe

Functions of the pituitary gland

Each lobe of the pituitary gland produces certain hormones.

Anterior lobe

Growth hormone.
Prolactin – to stimulate milk production after giving birth.
ACTH (adrenocorticotropic hormone) – to stimulate the adrenal glands.
TSH (thyroid-stimulating hormone) – to stimulate the thyroid gland.
FSH (follicle-stimulating hormone) – to stimulate the ovaries and testes.
LH (luteinizing hormone) – to stimulate the ovaries or testes.

Intermediate lobe

Melanocyte-stimulating hormone – to control skin pigmentation.

Posterior lobe

ADH (antidiuretic hormone) – to increase absorption of water into the blood by the kidneys.
Oxytocin – to contract the uterus during childbirth and stimulate milk production.