MGF 2mg

What is MGF ?

Mechano growth factor (MGF) is the 24-residue E-domain peptide released from IGF-1Ec after exercise-induced splicing in muscle tissue (Tyr-Gln-Pro-Pro-Ser-Thr-Asn-Lys-Asn-Thr-Lys-Ser-Gln-Arg-Arg-Lys-Gly-Ser-Thr-Phe-Glu-Glu-His-Lys). Research has examined its role in satellite cell activation and muscle cell proliferation following mechanical load.

MGF, short for mechano growth factor, is the 24-residue C-terminal E-domain peptide of the IGF-1Ec splice variant of insulin-like growth factor 1. It is proposed to be cut from the IGF-1 precursor when the mature 70-residue hormone is processed. No natural MGF peptide has yet been isolated from cells, tissues or body fluids (Matheny, Nindl and Adamo, Endocrinology, 2010). Yang and colleagues (J Muscle Res Cell Motil, 1996) cloned the splice variant from stretched rabbit muscle. The MGF name was given first to that mRNA and later to the synthetic peptide.

The peptide is strongly basic, with four lysines and two arginines. It has no methionine, cysteine or tryptophan, so it carries none of the oxidation-prone residues found in many research peptides. Each MGF 2mg vial holds white lyophilised powder.

MGF Research Applications

• Myoblasts : Yang and Goldspink (FEBS Lett, 2002) reported that the E domain increased myoblast proliferation and inhibited terminal differentiation, unlike mature IGF-1.
• Receptor : in the same study an IGF-1 receptor antibody did not block the effect, which points to a different receptor.
• Muscle damage : in damaged rat muscle, MGF mRNA rose quickly and fell within days, alongside satellite cell activation markers. Splicing then moved towards IGF-1Ea (Hill and Goldspink, J Physiol, 2003).
• Mechanical load : Yang and colleagues (1996) detected the splice variant within 2 hours to 6 days of altered activity, with very little in control muscle.
• Ageing : under mechanical overload, aged rat muscle expressed much less MGF than young muscle (Owino, Yang and Goldspink, FEBS Lett, 2001).

Typical in-vitro endpoints are proliferation and activation assays in myogenic cell lines and primary muscle stem cells. The evidence has limits. The positive data come mostly from one group. Fornaro and colleagues (Am J Physiol Endocrinol Metab, 2014) found that MGF at up to 500 ng/ml did not increase proliferation of C2C12 cells or primary human myoblasts. Every cell type in that study responded to mature IGF-1. No dedicated receptor has been identified, and there are no clinical data.

MGF vs PEG-MGF

Both products contain the same 24-residue E-domain sequence. MGF is the unmodified peptide, the form used by Yang and Goldspink (FEBS Lett, 2002). PEG-MGF carries a polyethylene glycol chain, a modification designed to slow clearance and protease breakdown. That adds a pharmacokinetic variable on top of biology that is already contested (Matheny, Nindl and Adamo, Endocrinology, 2010). MGF is the right choice for replication work, because it matches the published molecule.

Research Overview

MGF, short for mechano growth factor, is the 24-residue C-terminal E-domain peptide of the IGF-1Ec splice variant of insulin-like growth factor 1, sequence Tyr-Gln-Pro-Pro-Ser-Thr-Asn-Lys-Asn-Thr-Lys-Ser-Gln-Arg-Arg-Lys-Gly-Ser-Thr-Phe-Glu-Glu-His-Lys, written YQPPSTNKNTKSQRRKGSTFEEHK, molecular weight 2866.4 g/mol. It is the peptide cleaved from the IGF-1 precursor during processing of the mature 70-residue hormone, and it is expressed from an exercise-sensitive splice form of the IGF-1 gene that appears in muscle tissue after mechanical load. Research has examined its role in satellite cell activation and muscle cell proliferation following mechanical load.

The peptide was cloned and characterised in stretched skeletal muscle by Yang and colleagues, who reported the IGF-1 isoform and named the splice variant mechano growth factor (J Muscle Res Cell Motil, 1996). In the founding functional study, Yang and Goldspink (FEBS Lett, 2002) reported that the synthetic E-peptide increased myoblast proliferation while mature IGF-1 promoted differentiation, and Hill and Goldspink (J Physiol, 2003) reported that MGF expression in rodent muscle coincided with markers of muscle satellite (stem) cell activation after local tissue damage. Owino, Yang and Goldspink (FEBS Lett, 2001) reported that aged rat muscle expressed markedly less MGF in response to mechanical overload than young muscle.

It is worth being direct about the state of the evidence, because MGF is a peptide whose early findings have not been reproduced consistently. The primary positive data originate mostly from one research group, in rodent models and cell culture, and no human data exist for the peptide. Fornaro and colleagues (Am J Physiol Endocrinol Metab, 2014) tested native and stabilised MGF peptides on myoblasts and primary muscle stem cells and reported no effect on proliferation or activation in systems where mature IGF-1 produced a robust response, and the balanced review by Matheny, Nindl and Adamo (Endocrinology, 2010) concluded that the evidence for MGF as an in-vivo product of IGF-1 gene expression with a repair role is inadequate. No dedicated receptor for the peptide has been identified.

That contested status is precisely why it remains an interesting research tool rather than a settled one, and it is stated plainly here rather than papered over with confident mechanism claims. MGF is not an approved medicine in any jurisdiction and is supplied as lyophilised powder for in-vitro laboratory research only.

Storage and Reconstitution

Move vials to the freezer on arrival and keep them dark and dry. With no labile residues in the sequence, sterility sets the in-use limit more than chemistry. Split reconstituted stock into single-use aliquots instead of puncturing one vial again and again.

Vials are sold on their own, without bacteriostatic water for mixing or other supplies.

How to reconstitute and handle

• Handle under aseptic laboratory conditions using sterile equipment throughout reconstitution and aliquoting, and minimise stopper-open time.
• Avoid repeated freeze-thaw cycles. Prepare measured single-use aliquots from reconstituted stock for consistent experimental use.

For the full method, see the peptide reconstitution guide and the reconstitution calculator.

Research References

• Different roles of the IGF-I Ec peptide (MGF) and mature IGF-I in myoblast proliferation and differentiation (Yang and Goldspink, FEBS Lett, 2002)
• Expression and splicing of the insulin-like growth factor gene in rodent muscle is associated with muscle satellite (stem) cell activation following local tissue damage (Hill and Goldspink, J Physiol, 2003)
• Minireview: Mechano-growth factor: a putative product of IGF-I gene expression involved in tissue repair and regeneration (Matheny et al., Endocrinology, 2010)

Published research on MGF is indexed on PubMed. See our full UK buyer's guide for MGF.