The present invention relates to methods for inhibiting myostatin, a regulator of muscle mass, for muscle enhancement (including inducing hypertrophy and/or hyperplasia) as well as improving muscle function (including decreasing atrophy and/or increasing endurance, force and/or strength). Some of the methods involve delivering genes to cells using gene delivery or other delivery techniques known in the art in order to inhibit myostatin. Examples of genes to be delivered are genes encoding proteins such as Follistatin, Follistatin-related gene-1 (FLRG-I), growth differentiation factor associated protein- 1 (GASP-I) and myostatin precursor propeptide. The genes can be delivered using, for example, a recombinant Adeno-associated virus (rAAV), lentivirus or equine-associated virus capable of infecting the cells. Following introduction, the genes are expressed in the cell body of the infected cell and the encoded proteins are secreted systemically. In other methods of the invention expression of proteins such as activin lib and myostatin is inhibited by oligonucleotide techniques to effect muscle enhancement. All the methods have applications in the treatment of musculoskeletal and neurodegenerative disorders among others, as well as enhancing muscle in livestock.
