Question: 

The pro-hormone 19-Norandrostenedione (NOR) displays SARM-like properties with its low androgenic and high anabolic effects. Therefore NOR could play an essential role in the treatment of muscle dystrophies. Moreover, it could be abused for doping purposes in sports. To better understand the physiological effects of the substance, the influence of NOR on the proliferation and differentiation behaviour of C2C12 myoblasts was closer investigated.

Methods: 

C2C12 cells were incubated with medium containing NOR over a time period of five days. Cell proliferation was analyzed using Ki67-immuno staining as well as BrdU-assaying. Furthermore, apoptosis induction was investigated by activated Caspase-3 immuno staining. In order to gain information on the differentiation behavior of C2C12 cells myogenin and myosin heavy chain (MHC) were analyzed by immunocytochemical staining as well as western blotting.

Results: 

In proliferating conditions, NOR seems to enhance cell expansion, whereas apoptosis seems to only be slightly inhibited by the substance. Under differentiation conditions NOR seems to further decrease proliferation. Expression of the early differentiation marker myogenin protein content was enhanced by NOR in contrast to the terminal differentiation marker MHC where no difference in content was found between treated and untreated cells.

Conclusion: 

NOR seems to exhibit an enhancing effect on the proliferation and early differentiation in C2C12 myoblasts whereas the terminal differentiation marked by MHC content appears not to be affected. Further investigations are necessary to elucidate the underlying mechanisms and functional effects of NOR in myoblasts.