|Want to learn more about fiber types? ➫ review past SuppVersity articles|
AAS +/- HIT = ?
Basically the question the researchers from the universities of Campinas (Brazil) and Ohio had in mind, when they came up with their study protocol was: Do anabolic steroids exert direct effects on the fiber type composition and cross-sectional area of skeletal muscle fibers of sedentary and high-intensity, aerobically-exercised transgenic mice.
|DHT & T ⇔ fat & muscle Comp | more|
- Does the interaction of anabolic hormone treatment and high-intensity aerobic exercise produce an increase in muscle mass and redistribution of skeletal muscle fiber types?
- Are muscles with distinct metabolic and contractile properties (i.e., fast/glycolytic vs. slow/oxidative) differently modulated by the anabolic androgenic steroid treatment combined with a high-intensity, endurance-type training program?
- As such, three skeletal muscles were studied under these experimental conditions: soleus (SOL), tibialis anterior (TA) and gastrocnemius (GAS).
|Table 1: Overview of the incremental exercise program the rodents in the "EX-" (=exercise) groups performed on a treadmill 5x per week|
- Sed-C - sedentary control
- Sed-M - sedentary + 3x2mg/kg* Mesterolone per week
- Ex-C -5x/week HIT exercise + gum arabic placebo
- Ex-M - 5x/week HIT exercise + 3x2mg/kg* M per week
*Note: The scientists claim to administer "supraphysiological" against that background we must assume that we are talking about 2mg/kg for a human (if that was the rodent dose, the human equivalent) would be 12-15mg and that's clearly not "supra-physiological" - 3 doses of 150-200mg of Mesterolone which comes in 25mg pills, on the other hand, would be "supra-phyiological".After 6 weeks, the animals were sacrificed, their muscles harvested and an analysis of the entire range of pure and hybrid fiber types was conducted.
Mesterolone is not DHT: Anonymous was kind enough to remind me that the original version of this article did not make a clear distinction between DHT and 1-alpha-methyl-DHT aka Mesterolone (or Proviron). He did however mix his facts up, because contrary to A.'s claim Mesterolone has a 3x higher binding affinity for the androgen receptor in skeletal muscle than "regular" DHT (Saartok. 1984). With a 4x higher affinity for SHBG, it is however difficult to predict the real-world differences. This is particularly true in view of the fact that the growth response could be triggered by non-receptor mediated mechanisms, as well.Just in case you don't remember all the details you've learned about the different fiber types in previous SuppVersity articles, keep in mind that type I fibers are mainly oxidative, they use fat as a "preferred" substrate and will get you from A to B when you walk or jog. The type II fibers, on the other hand are "glycolytic", this means, that they rely heavily on glucose. Their prerogative are explosive / fast contractions and they carry the lions share of the weight you through around at the gym.
|Figure 1: Muscle weight and body weight (in g) at the end of the study (Fontana. 2013)|
|Figure 2: Detailed analysis of the changes in fiber type composition of soleus, tibialis and gastrocnemius muscle; all data expressed relative to sedentary control (Fontana. 2013)|
- Fontana, Karina, et al. "Effects of Anabolic Steroids and High-Intensity Aerobic Exercise on Skeletal Muscle of Transgenic Mice." PloS one 8.11 (2013): e80909.
- Itil, Turan M., et al. "Male hormones in the treatment of depression: effects of mesterolone." Progress In Neuro-Psychopharmacology 2.4 (1978): 457-467.
- Ly, Lam P., et al. "A double-blind, placebo-controlled, randomized clinical trial of transdermal dihydrotestosterone gel on muscular strength, mobility, and quality of life in older men with partial androgen deficiency." Journal of Clinical Endocrinology & Metabolism 86.9 (2001): 4078-4088.
- Saartok, Tönu, Erik Dahlberg, And Jan-Åke Gustafsson. "Relative binding affinity of anabolic-androgenic steroids: comparison of the binding to the androgen receptors in skeletal muscle and in prostate, as well as to sex hormone-binding globulin." Endocrinology 114.6 (1984): 2100-2106.
- Singh, Keerti, Asha Singh, and A. K. Sarada. "Assessment of mesterolone therapy in oligospermic males." www.ijpsi.org Volume 2 Issue 3 March 2013.