What is the Origin of Mechano-Growth Factor?

The term originated in molecular endocrinology and exercise physiology, following the discovery of the IGF-1 gene's complex alternative splicing patterns. The 'Mechano' prefix was assigned to this particular isoform because its expression is uniquely and robustly induced by mechanical strain on the muscle fiber. This discovery provided a molecular explanation for how physical exercise directly translates into anabolic signaling and tissue repair, distinguishing this local factor from the endocrine actions of circulating IGF-1.

What is the Mechanism of Mechano-Growth Factor?

Following mechanical stress, the IGF-1 gene is rapidly spliced to produce MGF, which contains a unique E-peptide domain. This E-peptide binds to specific receptors on quiescent muscle satellite cells, initiating their activation and proliferation. This surge of newly activated cells is essential for the repair of damaged muscle tissue and the subsequent fusion of these cells into existing muscle fibers, leading to myofiber hypertrophy. The localized, pulsatile nature of MGF action is a key regulatory mechanism for muscle adaptation and hormonal responsiveness to physical activity.

Mechano-Growth Factor

Meaning

Mechano-Growth Factor (MGF) is a splice variant of the Insulin-like Growth Factor 1 (IGF-1) gene, specifically produced in muscle tissue in response to mechanical overload or damage, such as from resistance exercise. It functions as a potent local autocrine and paracrine factor, playing a crucial role in initiating the repair and hypertrophy of muscle fibers. Unlike systemic IGF-1, MGF’s primary action is localized, serving as a critical signal to activate muscle satellite cells and promote muscle stem cell proliferation and differentiation, which is fundamental to maintaining musculoskeletal health and metabolic function.