Ladies and Gentlemen...this is something we have LONG suspected and is now becoming clear. On the news of this study release, I'm going to open up 2 more MyoSynergy logs - for people that take a Burst/Cruise approach to anabolic cycling.
With Androgen receptor activity having a direct increase effect on myoStatin, as a lot of you might have also thought, it appears that this very well might be responsible for the plateau and diminished effects of longer cycles.
So...if you would like to put your name in for a long of this nature, hit up the log page and make sure you know you are applying for the CB (cruise-burst) log position.
FASEB J. 2014 Mar 26. [Epub ahead of print]
A satellite cell-specific knockout of the androgen receptor reveals myostatin as a direct androgen target in skeletal muscle.
Dubois V1, Laurent MR, Sinnesael M, Cielen N, Helsen C, Clinckemalie L, Spans L, Gayan-Ramirez G, Deldicque L, Hespel P, Carmeliet G, Vanderschueren D, Claessens F.
Author information
Abstract
Androgens have well-established anabolic actions on skeletal muscle, although the direct effects of the androgen receptor (AR) in muscle remain unclear. We generated satellite cell-specific AR-knockout (satARKO) mice in which the AR is selectively ablated in satellite cells, the muscle precursor cells. Total-limb maximal grip strength is decreased by 7% in satARKO mice, with soleus muscles containing ∼10% more type I fibers and 10% less type IIa fibers than the corresponding control littermates. The weight of the perineal levator ani muscle is markedly reduced (-52%). Thus, muscle AR is involved in fiber-type distribution and force production of the limb muscles, while it is a major determinant of the perineal muscle mass. Surprisingly, myostatin (Mstn), a strong inhibitor of skeletal muscle growth, is one of the most androgen-responsive genes (6-fold reduction in satARKO) through direct transcription activation by the AR. Consequently, muscle hypertrophy in response to androgens is augmented in Mstn-knockout mice. Our finding that androgens induce Mstn signaling to restrain their own anabolic actions has implications for the treatment of muscle wasting disorders.-Dubois, V., Laurent, M. R., Sinnesael, M., Cielen, N., Helsen, C., Clinckemalie, L., Spans, L., Gayan-Ramirez, G., Deldicque, L., Hespel, P., Carmeliet, G., Vanderschueren, D., and Claessens, F. A satellite cell-specific knockout of the androgen receptor reveals myostatin as a direct androgen target in skeletal muscle.
KEYWORDS:
DNA response element, fiber type, hormone response element, microarray, mouse model
PMID:
24671706
[PubMed - as supplied by publisher]