|Parr et al. suggest that ecdysterone should be added to the WADA list.|
In the corresponding study, Parr and colleagues had tested the effects of ecdysterones on the fiber sizes of the soleus muscle (that's mainly slow twitch muscle fibers) of rodents in vivo and in vitro.
In the less relevant in vitro study, the researchers incubated C2C12 derived myotubes with the test compounds and determination of diameters of 47 myotubes per group (mean of measurements every 10–20 µm along the myotube) by fixing the cells and using photographs of the stained cells to determine the myotube diameters of 50 myotubes every 10–20 µm along the length of the myotube (further details see Parr. 2014). As the authors point out, incubation with ecdysterone showed "sign. increased myotube diameters compared to vehicle treated control cells" (Parr. 2015 | see Figure 1).
|Figure 1: Myotube diameter in the in vitro study after incubation with DHT, IGF-1 or Ecdysterone (Parr. 2015).|
How does ecdysterone work? Previous studies already confirmed the beneficial effects of ecdysterone on skeletal muscle protein synthesis. As early as in the year 2000, V.N. Syrov published a paper in the Pharmeceutical Chemistry Journal in which the beneficial effects ecdysterone and related agents on rodent muscles were documented. Later on, Gorelick-Feldman et al. proposed direct or indirect stimulation of the PI3K/Akt signaling pathway as mechanism for this increased protein synthesis (Gorelick-Feldman. 2008 & 2010). In the study at hand, Parr et al conducted molecular modeling experiments which appear to confirm that the effects of ecydesterone are mediated by estrogen-receptor-β (ERβ) binding, rather than via the androgen receptor which is the target of the many of the other drugs used.Obviously, the effects of bathing individual cells in concentrated ecdysterone cannot serve as a reliable litmus test for the anabolic prowess of an agent bodybuilders take as an oral supplement in dosages of usually no more than 1g per day. In this respect, the concomitantly conducted experiment with intact rodents is of much greater interest. In this part of study, the authors fed male Wistar rats (n = 42, Janvier, Le-Genest St-Isle, France) either 5 mg/kg body weight of ecdysterone, metandienone, estradienedione, or the selective androgen receptor modulatar (SARM) S-1, each diluted in a solution of 20% DMSO and 80% peanut oil daily. In that, it is unfortunately not 100% quite clear if the scientists used intraperitoneal or intra-muscular injections, but the composition of the "supplement" and the fact that a previous study (Syrov. 2000) used the same dosage orally, appear to suggest that Parr et al. refer to about IP injections, which mimic oral supplementation, but have the advantage of giving rodents no chance to regurgitate the drug, when they write that the rodents "received injections". What is pretty clear, though, is that the scientists used changes in muscle fiber size of the soleus muscle of male Wistar rats as measure of the anabolic potency of their test substances.
|Figure 2: Anabolic effect of ecdysterone (Ecdy) expressed as fiber size of soleus muscle in intact rats (Parr. 2015).|
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- Gorelick-Feldman, Jonathan, Wendie Cohick, and Ilya Raskin. "Ecdysteroids elicit a rapid Ca 2+ flux leading to Akt activation and increased protein synthesis in skeletal muscle cells." Steroids 75.10 (2010): 632-637.
- Parr, Maria Kristina, et al. "Estrogen receptor beta is involved in skeletal muscle hypertrophy induced by the phytoecdysteroid ecdysterone." Molecular nutrition & food research 58.9 (2014): 1861-1872.
- Parr, M. K., et al. "Ecdysteroids: A novel class of anabolic agents?." Biology of sport 32.2 (2015): 169.
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