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IGF-1 Bioavailability

Meaning

IGF-1 Bioavailability refers to the fraction of Insulin-like Growth Factor 1 (IGF-1) that is unbound to its primary carrier proteins, primarily IGF-Binding Protein 3 (IGFBP-3), and is therefore physiologically active and capable of binding to its cellular receptors. IGF-1 is a key mediator of growth hormone (GH) action, promoting anabolic processes like tissue growth and repair. Clinically, understanding the bioavailability is crucial because the total IGF-1 level may be high, yet the free or available fraction, which drives the biological effect, may be suboptimal, influencing clinical manifestations of GH deficiency or excess.