Insulin-Like Growth Factor-I (IGF-I), also known as somatomedin C, is a single-chain polypeptide hormone structurally similar to insulin, which serves as the primary mediator of Growth Hormone (GH) action in the body. Produced predominantly by the liver, IGF-I acts in an endocrine, paracrine, and autocrine fashion to stimulate systemic body growth, cell proliferation, and inhibit programmed cell death. Its circulating level is a reliable clinical marker for assessing overall GH status and diagnosing deficiency or excess.
Origin
The term originated from the observation that the effects of GH on cartilage and growth were mediated not by GH itself but by a circulating factor, initially termed “sulfation factor” and later “somatomedin.” The factor’s structural similarity to insulin led to its final designation as Insulin-Like Growth Factor-I. This discovery redefined the somatotropic axis, establishing the GH-IGF-I cascade as the central paradigm of growth regulation.
Mechanism
Growth Hormone stimulates the liver to synthesize and secrete IGF-I, which then travels through the bloodstream bound to specific binding proteins (IGFBPs). IGF-I exerts its effects by binding to the IGF-I receptor, a tyrosine kinase receptor, on target cells in various tissues, including bone, muscle, and cartilage. This binding activates intracellular signaling pathways, such as the PI3K/Akt and MAPK cascades, promoting cell growth, differentiation, and anabolic processes throughout the lifespan.
Long-term safety of growth hormone peptides relies on monitoring IGF-I, glucose metabolism, and broader endocrine markers to maintain physiological balance.
Growth hormone therapies, when precisely administered for deficiency, generally offer long-term benefits with manageable risks, requiring individualized clinical oversight.
We use cookies to personalize content and marketing, and to analyze our traffic. This helps us maintain the quality of our free resources. manage your preferences below.
Detailed Cookie Preferences
This helps support our free resources through personalized marketing efforts and promotions.
Analytics cookies help us understand how visitors interact with our website, improving user experience and website performance.
Personalization cookies enable us to customize the content and features of our site based on your interactions, offering a more tailored experience.