an adenohypophyseal hormone that accelerates the longitudinal growth of an organism’s bones and the organism’s overall body growth. It also helps regulate carbohydrate, lipid, and protein metabolism.
Growth hormone is synthesized by acidophilic cells of the anterior pituitary and secreted into the blood, where it is rapidly broken down. Human growth hormone is a protein with a molecular weight of 21,500. Its polypeptide chain consists of 191 amino-acid residues and contains two disulfide bridges. The primary structure of human, sheep, and ox growth hormone has been established.
The chemical structure of growth hormone has changed in different animals during the course of evolution, and the hormone has differentiated according to species. In man and sheep, for example, the hormones differ by a sequence of 70 amino-acid residues, which constitute more than one-third of the protein molecule. Therefore, animal growth hormone does not stimulate human growth, whereas human growth hormone is able to stimulate the growth of experimental animals (monkey growth hormone is closest to human growth hormone).
Increased secretion of growth hormone by the pituitary gland at an early age accelerates growth and causes gigantism. At a later age such increased secretion leads to acromegaly. A decrease in secretion results in hypophyseal dwarfism. This disease when detected in childhood responds to treatment by injections of growth hormone.
IU. A. PANKOV