Many hormones are involved in the growth and development of humans. It is still not clear exactly how they all interact to produce a fully developed adult but the importance of Human Growth Hormone (hGH) is known to be great. HGH is produced in the pituitary and it releases growth promoting factors, collectively called somatomedins, from the liver and other tissues. Somatomedin C increases cartilage production in the long bones mainly at the epiphyses.