Pituitary Disorders

The pituitary is an essential gland in the body, and diseases affecting it are generally defined by the effect they have on the hormones that the pituitary produces. The pituitary hormones control many of the important functions of the body. Many different pituitary disorders can occur and they interfere with the basic events of life, such as normal growth and reproduction, which necessitates treatment and support for those affected with these diseases by specialists across many health and social service fields.

The pituitary gland is a small, pea-sized gland located underneath the brain and behind the eyes. It is surrounded by a number of important structures, including the optic nerves, the hypothalamic region of the brain, and the internal carotid arteries. It lies in a bony area at the base of the skull (called the sella turcia, or Turkish saddle, due to its appearance). The pituitary gland has two main parts, the anterior part (called the adenohypophysis) and the posterior part (called the neurohypophysis). The adenohypophysis is thought to develop in humans by an outpouching of Rathke's pouch, which grows up from the mouth of the developing embryo. The neurohypophysis grows down from the developing brain. Both sections of the pituitary interact closely with the brain, and each produces different hormones.

The pituitary gland's function is to secrete hormones that control the other glands of the body. Most of the hormones are produced in the anterior portion. These hormones are important in growth, ovulation, breast milk production, and control of the thyroid and adrenal glands. Most of the disorders of the pituitary result in either too much or not enough of these hormones being produced.

Growth hormone is important throughout the body. It controls growth before and during puberty, and aids in controlling metabolism by influencing glucose levels in the blood. Occasionally, growth hormone can be produced in excess, such as in a pituitary tumor. This causes gigantism (large, tall individuals) if it occurs before puberty and acromegaly (enlargement of the limbs, facial features, and internal organs) if it occurs after puberty. It is essential that this condition be treated due to risk of other serious health problems such as diabetes and heart failure. Either medication or surgery may be used. Conversely, too little growth hormone can be produced, or the body can be resistant to it. This condition causes very short stature and delayed puberty, and is treated by giving extra growth hormone. The growth hormone is given as an injection. Previous growth hormone shortages have been rectified by a recombinant growth hormone that can be produced in a laboratory in large amounts.

Prolactin is a hormone essential for breast development and production of milk after pregnancy. When too much prolactin is produced, such as in a pituitary tumor [Page 1383]called a prolacinoma or certain medications, women can experience missed periods, inability to get pregnant, and nipple discharge. This can be treated by surgery or medication. If the pituitary is damaged during surgery, it may produce insufficient amounts of prolactin, and a woman may not be able to produce breast milk.

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