Insulin-like growth factor 1 Ec (IGF-1Ec)

Insulin-like growth factor 1 Ec (IGF-1Ec), commonly referred to as Mechano-growth factor (MGF) in muscle tissue, is a splice variant of the IGF-1 gene. It is primarily expressed in response to mechanical load or tissue injury, acting as a local autocrine/paracrine repair factor rather than a systemic hormone. IGF-1Ec contains a unique C-terminal E-peptide sequence that distinguishes it from the systemic IGF-1Ea isoform. Its primary biological role involves the activation and proliferation of satellite cells (muscle stem cells), which is crucial for muscle hypertrophy and the repair of damaged fibers. Beyond skeletal muscle, IGF-1Ec has shown potential neuroprotective effects and roles in cardiac tissue repair following injury. While synthetic versions like PEG-MGF have been investigated for treating muscle-wasting conditions, they are also notable for their history of misuse as performance-enhancing drugs in sports.

Other names

Mechano-growth factorMGFIGF-1 isoform 4IGF-1E peptideIGF-1Ec splice variant

Stimulates the proliferation of muscle stem cells (satellite cells) and promotes local tissue repair through signaling pathways distinct from systemic IGF-1, often acting in an autocrine/paracrine manner.