Human growth hormone (HGH) stimulates the growth of bones and affects the of , , and . It is secreted by the , which is located in the brain. Whereas HGH is produced in the body, genetic engineering has resulted in the development of recombinant human growth hormone (rHGH), which is used to treat stunted growth in children. Bovine somatotropin (BST) is a naturally occurring protein hormone in cows that increases milk production when administered as a supplement. BST is not biologically active in humans and is broken down into inactive and peptides when consumed. Therefore, milk from cows treated with BST is believed to be as safe and nutritious as milk from untreated cows.