What is the Origin of Term 37?

The term arose from the need to deconvolute the complex regulation of the somatotropic axis, which involves growth hormone (GH) acting on the liver to produce IGF-1, which then signals peripherally. Its development incorporated knowledge of the six IGF-binding proteins that modulate IGF-1 bioavailability. The 'Sensitivity Factor' highlights the focus on receptor-level response.

What is the Mechanism of Term 37?

IGF-1 exerts its anabolic and mitogenic effects by binding to the IGF-1 receptor (IGF-1R), initiating a PI3K/Akt signaling cascade that promotes protein synthesis and cell proliferation. IGFBPs primarily sequester IGF-1, limiting its access to the receptor; therefore, Term 37 attempts to correct for this binding interference. Cellular environments characterized by chronic inflammation or nutrient deprivation can impair the IGF-1R signaling components, leading to decreased functional sensitivity reflected by a lower index.

Term 37 ∞ Area

Term 37

Meaning

Term 37 is a composite index reflecting the efficiency of Insulin-like Growth Factor 1 (IGF-1) signaling in peripheral tissues, independent of circulating IGF-1 binding protein (IGFBP) saturation. This metric is essential for assessing growth potential, tissue repair mechanisms, and the anabolic drive mediated by growth hormone. A low Term 37 suggests tissue resistance to IGF-1 action, which can blunt the expected anabolic response to exercise or growth hormone administration. It provides a functional measure of the somatotropic axis downstream effects.