Brief Exposure to Steroids May be Permanently 'Remembered' by Muscles

It turns out that even a brief exposure to steroids could have long-term effects. Researchers have found that anabolic steroids could have possibly permanent, performance-enhancing effects. The findings reveal the importance of understanding how these drugs might impact the body.

Scientists once believed that the re-acquisition of muscle mass--with or without steroid use--after periods of inactivity was due to motor learning. Now, though, researchers have found that there may be a cellular "memory mechanism" within muscle of brief steroid users. In order to learn more about steroid use, though, the researchers examined mice.

"Mice were briefly exposed to steroids which resulted in increased muscle mass and number of cell nuclei in the muscle fibers," said Kristian Gunderson, one of the researchers, in a news release. "Three months after withdrawal of the drug (approximately 15 percent of a mouse's life span) their muscles grew by 30 percent over six days following load exercise. The untreated mice grew insignificantly."

In fact, the researchers found that greater muscle mass and more myonuclei, which are essential components for muscle fiber function, were apparent after the mice returned to exercise. These findings in particular may have consequences for the exclusion time of doping offenders; even brief exposure to anabolic steroids may have long last performance-enhancing effects.

"The results in our mice may correspond to the effects of steroids lasting for decades in humans given the same cellular 'muscle memory' mechanism," said Gundersen in a news release. "The new results might spur a debate on the current World Anti-Doping Agency (WADA) code in which the maximum exclusion time is currently two years."

The findings reveal a bit more about how muscle reacts in later life. In fact, the new data also suggests that strength training when young could be beneficial in later life since the ability to generate new myonuclei is impaired in the elderly.

The findings are published in the Journal of Physiology.