André K. Yamada

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Highlights:

Myostatin is a peculiar prototype that functions as a negative regulator of muscle mass.

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Myostatin limits muscle growth by binding to activin type II receptors (ActvRIIB) and type I receptors (ALK4 and ALK5). 

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Although inhibition of myostatin results in exacerbated muscle growth, it is not entirely clear how this is translated to the production of muscle force. 

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Among the regulatory genes, only oestrogen-related receptor γ was found to be up-regulated in response to exercise. It is known that over-expression of this gene promotes mitochondrial enlargement, angiogenesis and slow Myosin Heavy Chain expression.

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A more comprehensive approach would be to study humans, but inhibition of myostatin would not be ethical, and genetic manipulation, drugs and biopsy samples would be necessary.