An ecdysteroid is a type of steroid hormones in insects that are derived from enzymatic modification of cholesterol by p450 enzymes. This occurs by a mechanism similar to steroid synthesis in vertebrates. Ecdysone and 20-hydroxyecdysone regulate larval molts, onset of puparium formation, and metamorphosis. Being that these hormones are hydrophobic, they traverse lipid membranes and permeate the tissues of an organism. Indeed, the main receptor of these hormone signals - the ecdysone receptor - is an intracellularprotein.
In humans and other mammals
Use as supplement
20-Hydroxyecdysone and other ecdysteroids are marketed as ingredients in nutritional supplements for various sports, particularly bodybuilding. A comprehensive study, designed to find any strength or athletic improvement from 20-hydroxyecdysone, was published in 2006. The study looked for improvement in actual exercises performed and tested for improvements/increases in chemical indicators such as body composition and free/available testosterone. The results of the 2006 study concluded that using 30 mg per day of 20-hydroxyecdysone administered orally did not significantly affect anabolic or catabolic responses to resistance training, body composition, or training adaptations. However, a number of earlier studies supported the anabolic effects of 20-Hydroxyecdysone. A more recent study conducted in 2019 by a team that included the Department for Molecular and Cellular Sports Medicine at the German Sport University Cologne, found that significantly higher increases in muscle mass were observed in participants dosed with ecdysterone, with significantly more pronounced increases in one-repetition bench press performance. The study was funded by the World Anti-Doping Agency and demonstrated a significant dose-responsive anabolic effect of 20-Hydroxyecdysone supplementation on athletes during resistance training. Furthermore, recent studies have elucidated that the mechanism of action of 20-Hydroxyecdysone on humanmuscle cells is relatively selective activation of the beta form of the estrogen receptor, which is known to result in muscle hypertrophy.
Use as research tool
20-Hydroxyecdysone and other ecdysteroids are used in biochemistry research as inducers in transgenic animals, whereby a new gene is introduced into an animal so that its expression is under the control of an introduced ecdysone receptor. Adding or removing ecdysteroids from the animal's diet then gives a convenient way to turn the inserted gene on or off. At usual doses, 20-hydroxyecdysone appears to have little or no effect on animals that do not have extra genes inserted; it also has high bioavailability when taken orally, so it is useful for determining whether the transgene has been taken up effectively. For uses in gene therapy, it may be necessary to investigate more thoroughly the natural sources of ecdysteroids in humans. There is some in vitro evidence to show that 20-hydroxyecdysone has effects on some kinds of blood cells such as lymphocytes and neutrophils, and may act as an immunomodulator.
