Inhibition of myostatin – the key to hypertrophy?

Miostatin (GDF-8) is associated with the reduction of muscle growth in animals and humans, for now it has been unquestionably linked to its expression with sarcopenia. It may also be associated with increasing insulin resistance. There seem to be three proven methods for myostatin deletion of its gene, administration of anti-myostatin antibodies or administration of follistatin. 

Injection of anti-myostatin antibodies to mice results in a 20-fold increase in muscle mass and increases endurance for more than 4 weeks. Follistatin is an antagonist of transforming growth factor – beta. Certain compounds such as activin, transforming growth factor beta (TGFβ), L2 domain transcription factor, gonadotropin releasing hormone, zinc finger domain protein (GLI2), dexamethasone, androgens, WTT pathway activators (Winglessrelated integration site), 1.25 -dihydroxyvitamin D regulate the transcription of the follistatin gene. 2 Concentrations of GDF-8 inhibitors such as myostatin propeptide and follistatin have been tested in young people who have undergone strength or strength training. Training had no effect on the above myostatin inhibitors in the blood or in the muscles. Subjects with tetraplegia, non-trained persons and bodybuilders were also examined. The myostatin propeptide was raised only in the bodybuilding group. In testicular free rats, the myostatin condiment concentration was increased in the blood and muscles after testosterone administration. Training does not have a significant effect on myostatin inhibitors, and androgens are probably effective here. It even seems that strength training indirectly affects the increase in the amount of myostatin, but on the other hand, the activation of myostatin-like agents, such as follistatin, FSTL3 and SMAD-7, or genes that cause the expression of follistatin is activated. 4-5 Some studies show that regular aerobic training (when spending 1200 kcal per week) reduces muscle concentration by 37% myostatin. But how much this effect is translated into hypertrophy, we do not know. 

It is quite possible that myostatin inhibition has a future, although in humans agents like GDF-8 inhibitors (myostatin) do not work well.

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