Pfizer Genotropin is human growth hormone (HGH) protein manufactured by recombinant DNA technology. It has 191 amino acid residues and a molecular weight of 22, 125 daltons. It is identical structure to human growth hormone of pituitary origin. HGH is an important mediator of the human growth process. This hormone is produced endogenously by the anterior pituitary gland, and exists at especially high levels during childhood. Its growth-promoting effects are broad, and can be separated into three distinct areas: bone, skeletal muscle, and internal organs. It also supports protein, carbohydrate, lipid, and mineral metabolism, and can stimulate the growth of connective tissues.