ANDROGENS AND MUSCLE HYPERTROPHY

Skeletal muscle hypertrophy (growth) and androgens go hand in hand.  Unless you’re a genetic, myostatin-blocking mutant, it’s likely that gaining weight and muscle is harder than skydiving without a parachute. OK, maybe not that hard. Testosterone and many of its pharmaceutical derivatives are clearly the most effective of the anabolics (sorry, GH, IGF-1, insulin, etc.). Many androgens can be rightly used for treating wasting disorders, treatment of anemia and prevention of depression resulting from having too-low blood testosterone levels. Of course, some of the more intriguing biological questions surround how testosterone and its derivatives work. That is, what’s the mechanism? 
Androgen receptors, or the AR, are the likely candidates for where you should look to unlock the keys to how androgens exert their many varied effects. In fact, levels of androgen receptor are uniquely sensitive to circulating levels of androgen.1 However, in that study, DHT, or dihydrotestosterone, was administered to rats. DHT is a very androgenic steroid. There are better androgens (i.e., with greater anabolic activity and less androgenic activity).  Thus, scientists from the University of South Carolina sought to elucidate on the mechanisms by which a nandrolone decanoate, also fondly known as Deca-Durabolin or Deca, affected muscles in rats.  
Deca was given to rats at a dose of six milligrams per kilogram (mg/kg) body weight weekly for four weeks. This dose would be equivalent to 545 milligrams of Deca weekly for a 200-pound individual. That’s not what I’d consider a high dose, but certainly one that should exert anabolic effects. The rats getting the Deca were either young (five months) or old (25 months). The researchers found that Deca reduced body fat (measured in the abdomen around the kidneys) in the old rats, but not the young rats. Now, the odd part is that Deca had no effect on muscle weights. This, despite the fact that Deca increased AR protein significantly in both young and old rats. Interestingly, this effect was seen primarily in the slow muscle fiber types found in the soleus muscle (but not the fast-twitch dominant plantaris muscle).  

 What did they find? Testosterone didn’t change for any of the protocols.  The number of sets didn’t affect hormonal response in the MS protocol.  Cortisol and GH responses were greater after four sets compared to two sets in the MH and SE protocols, with no differences between the six-set and four-set sessions of the MH protocol.