Activin and FSH. Western blot analysis was performed as described in methods. (A) Proteins from control muscle, ovary, and liver were used as a normal sample, a positive control, and a negative control, respectively. (B) One microliter of serum was obtained from the pCMV-rAct-injected mice, electrophoresed, and performed to western blot as described in methods. The western blot shown is representative of results obtained from three independent experiments.