How does growth hormone work?
When growth hormone is released from the pituitary gland, it causes the release of a second growth-promoting hormone called insulin-like growth factor-1 (IGF-1). Together, growth hormone and IGF-1 signal growth and/or increased number of cells in bone, muscle, and many other organs and tissues. The growth of the bones also requires that bone cells add minerals such as calcium and phosphate so that the bones become strong. Growing strong bones requires both growth hormone and IGF-1.
