Ecdysterone, a steroid-like substance found in spinach, quinoa and bodybuilding supplements, has a stronger anabolic effect than scientists suspected. German biochemists have worked out how ecdysterone makes muscle fibres bigger and stronger – and they think that this natural steroid can help the elderly to maintain muscle strength. And that ecdysterone should perhaps be placed on the doping list.
Alpha and beta estrogen receptors
The female sex hormone estradiol attaches itself in cells to its estrogen receptor alpha and estrogen receptor beta. Via the alpha receptor estradiol stimulates the growth of the fatty layers on the hips and breasts, and aggression; via the beta receptor it keeps bones strong, maintains a healthy cholesterol balance and keeps the blood vessels supple – and muscle mass up to the mark.
The latter has been known more or less for sure since molecular scientists at the German Sport University in Cologne published an animal study in FASEB Journal, in which they gave castrated male a compound [Beta], which attaches itself specifically to the estrogen-beta-receptor. [FASEB J. 2012 May;26(5):1909-20.] The figure below shows the effect of injections of the substance on the Levator ani muscle.
TP = testosterone propionate; Flu = flutamide [a substance that blocks the effect of testosterone]; Intact = untreated, non-castrated rats; Orchi = untreated castrated rats.
Look at the evidence: compounds that stimulate the estrogen beta receptor have an anabolic effect in and of themselves, and also strengthen the anabolic effect of testosterone in muscle cells. They at least make sure that muscle cells produce more IGF-1 when they receive anabolic stimuli from testosterone.
Natural estrogen receptor beta agonists
Plant-based foods are rich in compounds that stimulate the estrogen receptor beta. Soya is one of the sources. This is probably why soya protein is such an effective muscle builder: although the amino acids in soya protein are not optimally suited to human needs, the effect of soya protein in a well-balanced diet is almost the same as that of the theoretically much better proteins found in dairy products. Some animal studies have shown that soya protein has an anticatabolic effect that is even bigger than that of casein. [Nutrition. 2002 Jun;18(6):490-5.]
If you also take into account the fact that many plant-based substances that stimulate the estrogen beta receptor also partly deactivate the estrogen alpha receptor, it’s difficult to see why so many bloggers claim that soya proteins are dangerous for men and that they cause impotence or breast formation. But never mind.
Ecdysterone
The same researchers in Cologne will soon publish the results of a new study in Molecular Nutrition and Food Research. In this they show in experiments done on male rats that ecdysterone – a compound sometimes found in bodybuilding supplements – stimulates muscle growth via the estrogen beta receptor.
Ecdysterone, together with other ecdysteroids, is found in large quantities in quinoa and spinach. Spinach is a particularly good source of ecdysteroids: one portion of cooked spinach can provide over 100 mg of them.
The researchers gave their lab animals 5 mg ecdysterone daily for three weeks. If you convert the dose to human proportions you arrive at 50-100 mg ecdysterone per day. The figures below show that this dose had a modest but noticeable anabolic effect on the rats’ leg muscles.
When the researchers exposed muscle cells from the rats not only to ecdysterone, but also to the anti-oestrogen ZK 283361 [Anti Beta], the anabolic effect of ecdysterone disappeared completely. ZK 283361 blocks the effect of the estrogen beta receptor.
When the researchers exposed muscle cells from the rats not only to ecdysterone, but also to the anti-oestrogen ZK 283361 [Anti Beta], the anabolic effect of ecdysterone disappeared completely. ZK 283361 blocks the effect of the estrogen beta receptor.
Conclusion
“Our data clearly confirm that ecdysterone is a compound with strong anabolic activity in vivo and in vitro, and that estradiol receptor-beta seems to be involved at least in vitro”, the researchers write. “This opens therapeutic perspectives for the treatment of muscle injuries, sarcopenia, and cachectic disease, but also needs to be considered with respect to classification of ecdysterone as a substance that could be misused for doping purposes.”
Estrogen receptor beta is involved in skeletal muscle hypertrophy induced by the phytoecdysteroid ecdysterone.
Abstract
SCOPE:
The phytoectysteroid ecdysterone (Ecdy) was reported to stimulate protein synthesis and enhance physical performance. The aim of this study was to investigate underlying molecular mechanisms particularly the role of ER beta (ER?).
RESULTS:
In male rats, Ecdy treatment increased muscle fiber size, serum IGF-1 increased, and corticosteron and 17?-estradiol (E2) decreased. In differentiated C2C12 myoblastoma cells, treatment with Ecdy, dihydrotestosterone, IGF-1 but also E2 results in hypertrophy. Hypertrophy induced by E2 and Ecdy could be antagonized with an antiestrogen but not by an antiandrogen. In HEK293 cells transfected with ER alpha (ER?) or ER?, Ecdy treatment transactivated a reporter gene. To elucidate the role of ER? in Ecdy-mediated muscle hypertrophy, C2C12 myotubes were treated with ER? (ALPHA) and ER? (BETA) selective ligands. Ecdy and BETA treatment but not ALPHA induced hypertrophy. The effect of Ecdy, E2, and BETA could be antagonized by an ER?-selective antagonist (ANTIBETA). In summary, our results indicate that ER? is involved in the mediation of the anabolic activity of the Ecdy.
CONCLUSION:
These findings provide new therapeutic perspectives for the treatment of muscle injuries, sarcopenia, and cachectic disease, but also imply that such a substance could be abused for doping purposes.
PMID: 24974955 [PubMed – as supplied by publisher]
