Growth hormone, or somatotropin, is a type of hormone that is produced and released by specialized cells in the anterior part of the pituitary gland, according to Colorado State University. The hormone plays a major role in several vital processes, including metabolism and growth. In some diseases, patients will experience an abnormal rise in the amount of growth hormone produced and secreted by the pituitary gland. This can have deleterious effects on the patient. Understanding the possible causes behind the increase in somatotropin will allow physicians to quickly and effectively treat the patient.
Tumors of the Pituitary Gland
Pituitary tumors are one of the more common causes of excess amounts of growth hormone, according to MayoClinic.com. The most common pituitary tumor is the benign, or non-cancerous, adenoma. This tumor is made up of cells, called somatotrophs, which rapidly synthesize and secrete growth hormone. These tumors often grow large enough to press against nearby tissues. The pituitary gland is located near the eyes and other cranial structures. A large tumor in the pituitary gland can cause headaches and impaired vision.
Multiple Endocrine Neoplasia Type I
Growth hormone levels increase in patients suffering from multiple endocrine neoplasia type I, or MEN-I, reports the National Endocrine and Metabolic Diseases Information Service. MEN-I is a genetic disorder that causes tumors to grown in the multiple endocrine organs. The disease is rare, typically occurring in one in 30,000 people. MEN-I can cause tumors in the pituitary gland. If the tumor is composed of cells that secrete growth hormone, the patient will develop significantly increased levels of growth hormone. This may lead to acromegaly or gigantism.
Non-Pituitary Tumors
Excessive levels of growth hormone can be caused by tumors located in the lungs, adrenal glands or pancreas, states MayoClinic.com. In rare cases, these tumors can secrete either growth hormone itself or a specific hormone called growth hormone-releasing hormone, or GH-RH. GH-RH increases the production of growth hormone by stimulating the pituitary gland. Surgical treatment to remove these tumors, usually allows somatotropin levels to return to normal.
McCune-Albright Syndrome
McCune-Albright syndrome is a genetic disease that can cause an increase in growth hormone production, according to the University of Maryland Medical Center. The disease is caused by a mutation in the GNAS1 gene. If tested, patients with this disease will have very high levels of growth hormone within their bodies. Patients will also have high levels of adrenal hormones and prolactin, which is another hormone produced by the pituitary gland. Common symptoms of this disease include premature puberty in young women, bone fractures, gigantism and deformities in the bones of the face.
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