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Growth Hormone Deficiency
What is it?
Individuals with GHD do not produce enough growth hormone, or somatotropin. Their growth typically begins to slow between the ages of 6 months and 3 years. By their third birthday they may be considerably shorter than their peers. Children with GHD also may have an immature facial appearance, and they may weigh more than other children of similar stature who don't have the condition.
Adults may have GHD, but their symptoms often do not include abnormal height. Their symptoms typically are more general than those experienced by children and may include fatigue, muscle weakness, an overall feeling being stressed, and other emotional problems.
Growth hormone is released from the pituitary gland and is required for appropriate growth. Growth hormone also plays an important role in the breakdown of carbohydrates and fats in the body. The pituitary gland is located in the middle of the skull, under the hypothalamus, at the base of the brain. Its two regions are called the anterior lobe, located in the front of the gland, and the posterior lobe, in the back. The pituitary gland is often called the master gland because it is responsible for the release of many important bodily hormones, including growth hormone, which is released from the anterior lobe. The hypothalamus controls the release of hormones from the pituitary gland's two lobes.
Growth hormone-releasing hormone signals the pituitary gland to release growth hormone. The release of growth hormone also is dependent on the presence of other substances such as adrenocorticotropic hormone; vasopressin (or anti-diuretic hormone); somatostatin (a hormone released by the hypothalamus); and growth hormone-releasing peptide; as well as on the individual's food intake, sleep pattern, exercise regimen, physical and mental stress, and medication use. Other factors that may affect the release of growth hormone by the pituitary gland, leading to growth hormone deficiency, include increased blood sugar after meals, elevated free-fatty acids, elevated insulin-like growth factor-I, progesterone, and many prescription drugs.
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What is it?
