Tópico: Baixas doses de ecdysteroids promovem crescimento muscular

Low doses of ecdysteroids promote muscle building

The amounts of ecdysteroids in bodybuilding supplements are probably sufficient to stimulate growth of muscle mass, write endocrinologists at the University of Goettingen, Germany, in an article that will appear soon in the Journal of Steroid Biochemistry and Molecular Biology. In trials, modest doses of the ecdysteroid 20-hydroxy-ecdysone [structural formula shown below] increased the muscle mass of rats and also reduced the amount of body fat.



We wrote recently about Dana Seidlova-Wuttke’s research project. Seidlova-Wuttke is a gynaecologist by training who specialises in the use of medicinal herbs. Her current research in Germany is on whether ecdysteroids are of use to <A href="http://www.google.com/custom?domains=ergo-log.com&q=post-menopausal&sa=+search+&sitesearch=ergo-log.com&client=pub-7117181179885591&forid=1&ie=ISO-8859-1&oe=ISO-8859-1&hl=enpost-menopausal</a">women. She already publish the results of a study that showed that ecdysterone strengthens the bones and joints of female rats. The animals Seidlova-Wuttke uses for her experiments have had their ovaries removed, so they produce very low levels of sex hormones.

In the study that will be published soon in the Journal of Steroid Biochemistry and Molecular Biology, the researchers gave rats 18, 56 or 116 mg ecdysterone orally every day. Control groups were given ordinary feed [ovx,sf] or feed containing a small amount of synthetic estradiol [ovx+E2].

The figures below show that the ovx+E2 rats had gained hardly any fat at all after 3 months. The ovx,sf rats had got fatter, but the rats that had been given ecdysteroids had gained less fat than the ovx,sf rats.





The fat on the shinbone is called paratibial fat. This is a marker for subcutaneous fat, which is the fat that lies under the skin. The higher doses of ecdysteroids inhibited the growth of the paratibial fat. And all doses inhibited the growth of visceral fat [intra-abdominal fat]. This is the fat that surrounds the organs in the abdominal cavity, which increases the risk of cardiovascular disease.

The figure below shows what happened to the lab animals’ muscle mass. The ecdysteroids had an anabolic effect.





The researchers concluded that the ecdysteroids did not have an estrogenic effect: they had no effect on the uterus of the rats. But estradiol did have an estrogenic effect.

For athletes the most interesting passages in the article concern the dose-effect relation of ecdysteroids. "A pharmacologic rule says that on the basis of per kg body weight rodents require approximately 10–15-fold higher doses of compounds in order to achieve the same effects as in humans", the researchers write. "Augmentations of muscle mass in the humans were described under a daily intake of 200 mg/person and bodybuilders consume gram-quantities of ecdysteroids. On the basis of these considerations our lowest dose corresponded to doses suggested for normal consumers whereas the highest dose corresponded to quantities taken by bodybuilders. Hence, doses used in the present study are relevant values for the human."

So a daily dose of several hundred milligrams of ecdysteroids should be enough to encourage muscle growth, according to this article. And perhaps ecdysteroids are also effective at even smaller doses.

"It was interesting to note that ecdysteroids at the tested doses resulted seldomly in a dose related response", the Germans write. "This may point to a bell-shaped dose–response curve which would mean that all 3 doses were in the peak range of the bell and that theoretically even lower doses could be effective on several parameters."

Source:
J Steroid Biochem Mol Biol. 2010 Jan 25. [Epub ahead of print].

pelo menos o titulo em portugues, please ;)

O composto em questão pode ser encontrado na boa e velha Vitex
Ecdysteroids from two Brazilian Vitex species.

dos Santos TC, Delle Monache F, Leitão SG.
Núcleo de Pesquisas de Produtos Naturais, Universidade Federal do Rio de Janeiro, CCS, Bloco H, Ilha do Fundão, 21.941-590, and INCQS/FIOCRUZ, Rio de Janeiro, Brazil
Abstract

A new ecdysteroid, 26-hydroxypinnatasterone (1), together with 20-hydroxyecdysone, was isolated from the stem barks of Vitex cymosa. 20-Hydroxyecdysone, ajugasterone C, ajugasterone C monoacetonide and turkesterone were isolated from the branches of V. polygama. The structure of 1 was determined by spectroscopic methods.

20-hydroxyecdysone reduces insect food consumption resulting in fat body lipolysis during molting and pupation.

Wang S, Liu S, Liu H, Wang J, Zhou S, Jiang RJ, Bendena WG, Li S.
Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
Abstract

The insect steroid hormone 20-hydroxyecdysone (20E) acts through a specific nuclear receptor complex, ecdysone receptor (EcR) and ultraspiracle (USP). EcR and USP are FXR/LXR and RXR orthologs, respectively, which play critical roles in the regulation of lipid metabolism in mammals. Lipid concentration in Bombyx hemolymph and lipase activity in fat body peaked during molting and pupation, suggesting that 20E induces lipolysis at these stages. Differing from their mammalian orthologs, the 20E-bound EcR-USP was not able to directly stimulate fat body lipolysis in both Bombyx and Drosophila. Instead in Bombyx, 20E slowly reduced food consumption and then induced starvation, resulting in fat body lipolysis. Molecular analysis revealed that the evolutionarily conserved adipose triacylglycerol lipase gene Brummer was transcriptionally up-regulated by 20E-induced starvation during molting and pupation. To our knowledge, this is the first report demonstrating that the steroid hormone 20E is a critical regulator of lipolysis in insects.



20-Hydroxyecdysone increases fiber size in a muscle-specific fashion in rat.

Tóth N, Szabó A, Kacsala P, Héger J, Zádor E.
Department of Pharmacognosy, Szeged, Hungary.
Abstract

20-Hydroxyecdysone (20E) is an ecdysteroid hormone that regulates moulting in insects. Interestingly, 20E is also found most abundantly in plant species and has anabolic effects in vertebrates, i.e. increasing muscle size without androgen influence. The effect of 20E on slow and fast fiber types of skeletal muscle has not been reported yet. Here we present that 20E affects the size (cross-sectional area, CSA) of the different fiber types in a muscle-specific manner. The effect on fiber size was modified by the distance from the site of the treatment and the presence of a regenerating soleus muscle in the animal. Besides the fiber size, 20E also increased the myonuclear number in the fibers of normal and regenerating muscles, suggesting the activation of satellite cells. According to our results 20E may provide an alternative for substitution of anabolic-androgenic steroids in therapeutic treatments against muscle atrophy.

Phytoecdysteroids increase protein synthesis in skeletal muscle cells.

Gorelick-Feldman J, Maclean D, Ilic N, Poulev A, Lila MA, Cheng D, Raskin I.
Biotech Center, Cook College, Rutgers University, 59 Dudley Road, New Brunswick, New Jersey 08901, USA. jongf@eden.rutgers.edu
Abstract

Phytoecdysteroids, which are structurally similar or identical to insect molting hormones, produce a range of effects in mammals, including increasing growth and physical performance. To study the mechanism of action of phytoecdysteroids in mammalian tissue, an in vitro cellular assay of protein synthesis was developed. In C2C12 murine myotubes and human primary myotubes, phytoecdysteroids increased protein synthesis by up to 20%. In vivo, ecdysteroids increased rat grip strength. Ecdysteroid-containing plant extracts produced similar results. The effect was inhibited by a phosphoinositide kinase-3 inhibitor, which suggests a PI3K-mediated mechanism.






PORÉM.....
Effects of methoxyisoflavone, ecdysterone, and sulfo-polysaccharide supplementation on training adaptations in resistance-trained males.

Wilborn CD, Taylor LW, Campbell BI, Kerksick C, Rasmussen CJ, Greenwood M, Kreider RB.
Human Performance Lab, University of Mary Hardin Baylor, Belton, TX.
Abstract

ABSTRACT : PURPOSE : Methoxyisoflavone (M), 20-hydroxyecdysone (E), and sulfo-polysaccharide (CSP3) have been marketed to athletes as dietary supplements that can increase strength and muscle mass during resistance-training. However, little is known about their potential ergogenic value. The purpose of this study was to determine whether these supplements affect training adaptations and/or markers of muscle anabolism/catabolism in resistance-trained athletes. METHODS : Forty-five resistance-trained males (20.5 +/- 3 yrs; 179 +/- 7 cm, 84 +/- 16 kg, 17.3 +/- 9% body fat) were matched according to FFM and randomly assigned to ingest in a double blind manner supplements containing either a placebo (P); 800 mg/day of M; 200 mg of E; or, 1,000 mg/day of CSP3 for 8-weeks during training. At 0, 4, and 8-weeks, subjects donated fasting blood samples and completed comprehensive muscular strength, muscular endurance, anaerobic capacity, and body composition analysis. Data were analyzed by repeated measures ANOVA. RESULTS : No significant differences (p > 0.05) were observed in training adaptations among groups in the variables FFM, percent body fat, bench press 1 RM, leg press 1 RM or sprint peak power. Anabolic/catabolic analysis revealed no significant differences among groups in active testosterone (AT), free testosterone (FT), cortisol, the AT to cortisol ratio, urea nitrogen, creatinine, the blood urea nitrogen to creatinine ratio. In addition, no significant differences were seen from pre to post supplementation and/or training in AT, FT, or cortisol. CONCLUSION : Results indicate that M, E, and CSP3 supplementation do not affect body composition or training adaptations nor do they influence the anabolic/catabolic hormone status or general markers of catabolism in resistance-trained males.


Tem bastante coisa para pesquisar, porém, sinceramente isso ai não abriu meu "apetite" para correr atrás de nada. Fiquem a vontade..

Tem esse outro estudo tb em relação a sua influencia sobre o tecido adiposo:

Ecdisteróides refream o crescimento do tecido adiposo

More plus factors for the ecdysteroids: the steroid compounds in spinach-type plants not only have an anabolic effect, but also curb the growth of fat layers. Researchers at Rutgers University will soon publish the results of a study which offers evidence that ecdysterone [also known as 20-hydroxyecdysone, structure below] prevents overfed mice from getting fat.
Correction: from getting too fat.


The same researchers have already published an article in which they showed that ecdysterone makes the muscle cells of rats grow faster. Ecdysterone also made the animals stronger. Hungarian researchers confirmed the results a few months later. According to their animal study, ecdysterone has an anabolic effect in slow muscle fibres.




In their latest publication the Americans examine whether ecdysterone is a suitable model for developing a new medicine for obesity and diabetes 2. That’s why they fed mice a diet that consisted of sixty percent fat for the experiment. [HF] The mice in the control group were given a diet containing only ten percent fat. [LF] Mice on this level of diet do not become fat.

Half of the high-fat diet mice were given a daily dose of 10 mg ecdysterone per kilo bodyweight. Orally. The experiment lasted thirteen weeks.

The table below shows the effect on insulin levels and the concentration of adiponectin. Adiponectin is a protein that is secreted by healthy fat cells sensitive to insulin. Adiponectin suppresses appetite and heightens the effect of insulin. And the other way round, if the cells’ insulin performance declines, the secretion of adiponectin also goes down. It looks as though ecdysterone helps reverse this process in mice that are putting on weight.


As the mice get fatter, the concentration of glucose in their blood rises. Apparently they can’t make enough insulin to process the glucose, or their insulin receptors are not working so well. But if the fat mice are also given ecdysterone this doesn’t happen.



This mechanism is probably how ecdysterone curbs the increase in bodyweight. The heaviest the mice in the control group got was 5.18 g, while the fattened mice weighed as much as 18.8 g. And the fattened mice that were given ecdysterone put on 18 percent less weight. At the end of the experiment they weighed 15.4 g. It is the growth of fat tissues that ecdysterone inhibits. The steroid has little effect on the increase of lean body mass.

Ecdysterone is found in supplements. Manufacturers seem to have been inspired mostly by almost occult studies from the Eastern Bloc on the effects of ecdysteroids. Although there is increasing evidence that ecdysteroids do have an effect, it is still not at all certain whether users of the ecdy-supplements that are currently available notice these. The doses are too low.

Sources:
Am J Physiol Endocrinol Metab. 2009 Jan 6. [Epub ahead of print].