Analysis of myostatin and its related factors in various porcine tissues.

Myostatin is expressed in skeletal muscle tissue where it functions to suppress myoblast proliferation and myofiber hypertrophy. Recently, myostatin was detected in the tendon, mammary gland, and adipose tissue of mice. We sought to determine whether myostatin is expressed in the liver, spleen, lung, and kidney of pigs. Real-time PCR and Western blots demonstrated that myostatin, follistatin, decorin, and activin receptor IIB (ActRIIB) mRNA and proteins were expressed in skeletal muscle, heart muscle, and adipose tissue, and also in liver, spleen, lung, kidney, and cultured fibroblasts. The relative abundance of myostatin was closely related to follistatin and decorin in porcine tissues. Immunohistochemical analysis further demonstrated the presence of myostatin, follistatin, and decorin in the skeletal muscle, adipose tissue, heart muscle, liver, spleen, lung, and kidney of pigs. These results suggest that myostatin could be associated with certain functions of the internal organs, such as energy metabolism or fibrosis. We conclude that myostatin is a factor broadly expressed in the internal organs and muscle tissues of pigs.