IGF-1

Full name: Insulin-Like Growth Factor-1

A 70-amino-acid peptide hormone produced primarily in the liver in response to growth hormone stimulation. The primary mediator of GH's anabolic effects on muscle, bone, and organ tissue. Activates the IGF-1 receptor (IGF-1R) and downstream PI3K/Akt/mTOR signaling pathways to stimulate cell proliferation, differentiation, and survival. Serum levels peak in late adolescence and decline progressively with age.