Figure 1.

Myostatin stimulates C2C12 proliferation. Cells were plated in DMEM/10% FBS, at a density of 3000 cells per well in a 96-well plate and cultured for 24 hours Medium was then replaced as indicated and cells were cultured for 48 hours with different concentrations of recombinant human myostatin (rhMSTN) and/or IGF-I. Two different myostatin recombinants were used: a commercially available peptide (R&D Systems) and another (Thompson) generated in our laboratory (15). Cell number was quantified and results are expressed as percent of serum-free (SF) control to account for interassay variance. Statistical comparisons are limited to within-treatment groups, and different letters indicate significant differences whereas the same letters signify no difference (P ≤ .05).