New study illustrates long-term effects of steroid use on muscle regain

A paper published in this month’s edition of the Journal of Physiology provides compelling evidence for the long-term beneficial effects of steroid use on muscle mass. This seminal finding – based on several experiments performed in mice – could revolutionise sentencing for drugs cheats in professional sport.

“Anabolic” steroid hormones such as testosterone exert a profound influence upon various tissues of the body. Besides their involvement in the regulation of metabolism and mood, these hormones have also been implicated in the deposition of muscle mass. Previous studies have demonstrated that strength training early in life significantly facilitates the re-acquisition of muscle mass after long periods of relative inactivity – an effect mimicked by anabolic steroids. The Norwegian team, led by Dr Ingrid Enger, sought to uncover the cellular mechanism underlying this “muscle memory” phenomenon.

The researchers treated adult female mice with testosterone for 14 days and noted a 77% increase in the cross-sectional area of the composite myofibrils of the skeletal muscle. Crucially, they also observed a 66% rise in the number of nuclei within these cells. When the drug was removed for three months, myofibril size returned to normal but the elevated number of nuclei was retained. After this period of muscle loss, skeletal muscles were subjected to “overload”, an experimental paradigm which promotes adaptive muscle growth. Rapid re-growth was observed in mice which had received testosterone injections three months previously but not in age-matched controls.

The three month period of withdrawal following testosterone treatment is equivalent to approximately ten years of human life. As such, if the cellular basis of this “muscle memory” phenomenon is confirmed in human subjects, it may have far-reaching consequences for doping policy. WADA’s current recommendation for doping bans – a mere two years – may soon become defunct.

Article available at: http://onlinelibrary.wiley.com/store/10.1113/jphysiol.2013.264457/asset/jphysiol.2013.264457.pdf?v=1&t=hndubazr&s=b02331881db66b1c78d723f8100cc7d91cc5adf8