Growth Hormone

Growth Hormone, substance, necessary for human growth, that is produced by the anterior lobe of the pituitary gland. The hormone effects uptake of amino acids and metabolism of fats. It also stimulates secretion by the liver of the hormone somatomedin, which carries out bone formation. Secretion of growth hormone is increased by exercise, stress, and lowered glucose intake and by insulin and the estrogens. Release of growth hormone is inhibited by a protein called somatostatin, which is produced by the hypothalamus, a brain structure that probably also produces a factor that stimulates the release of growth hormone.

Pathological conditions associated with abnormal growth-hormone synthesis include gigantism, caused by an excess of the hormone during childhood; acromegaly, resulting from overproduction of growth hormone in adulthood; and dwarfism, caused by underproduction of the hormone in childhood. Overproduction syndromes appear to respond to administration of somatostatin, and dwarfism to administration of growth hormone. Scientists have developed a process for making human growth hormone by genetic engineering, and several drugs are available to treat children with short stature resulting from a deficiency of growth hormone.