What is the Origin of Hepatic IGF-1 Production?

The term originates from the discovery that Growth Hormone (GH) did not directly stimulate growth in peripheral tissues but instead induced the release of an intermediary factor from the liver, initially called "sulfation factor" or "somatomedin." This factor was later identified as IGF-1, confirming the liver's role as the endocrine hub of the GH axis. The term hepatic simply refers to the liver.

What is the Mechanism of Hepatic IGF-1 Production?

The production of IGF-1 is directly stimulated when Growth Hormone, secreted by the pituitary gland, binds to its specific receptors on the surface of hepatocytes, or liver cells. This binding activates intracellular signaling pathways, most notably the JAK-STAT pathway, which increases the transcription and eventual release of IGF-1 into the bloodstream. Circulating IGF-1 then mediates many of the anabolic and growth-promoting effects of GH on skeletal muscle and bone.

Hepatic IGF-1 Production

Meaning

Hepatic IGF-1 production refers to the synthesis and subsequent secretion of Insulin-like Growth Factor-1, a crucial anabolic peptide hormone, primarily by the liver. The liver is the major source of circulating, endocrine IGF-1 in the body. This process is a central component of the somatotropic axis, regulating growth and metabolism.