20-Hydroxyecdysone bioavailability and pharmacokinetics in Gerbillus tarabuli, a gerbil model for metabolic syndrome studies.

Phytoecdysteroids are active natural compounds that have demonstrated many beneficial pharmacological effects on mammals, including Humans. 20-Hydroxyecdysone (20E) is the major phytoecdysteroid present in plants, and gerbils are particularly good responders to the addition of 20E to their diet. We have examined the oral bioavailability of 20E in the desert gerbil, Gerbillus tarabuli. 20E (5 and 50 mg.kg body weight) was administered to gerbils by intra-peritoneal injection and oral gavage, respectively. Plasma samples were collected over 8 h and analyzed by HPLC-MS/MS to determine the 20E concentrations. The calculated oral bioavailability of 20E is approx. 12%, with a half-life of 30.6 and 33 min after per os administration or intra-peritoneal injection, respectively. This bioavailabilitty is much higher than that observed in laboratory rodents (ca. 1%). It is proposed that this unexpectedly high oral bioavailability of 20E in gerbils contributes to its high efficacy in this animal.