A hormone which stimulates the growth of bones and muscles in juvenile animals (including human children). It can also be artificially added to adult domestic animals to increase the growth of muscles or production of milk in adult animals (see porcine somatotropin and bovine somatotropin). It is produced by the pituitary gland in the brain.
 
Glossary
Definition:
a hormone produced by the pituitary gland; essential for normal growth.