Ecdysteroids: biochemical mechanism of 20-hydroxyecdysone inactivation in Triatoma infestans (Hemiptera, Reduviidae).

When 3H-20-hydroxyecdysone was injected into Triatoma infestans during the fifth nymphal instar, it was converted to very polar metabolites (peak 1). The polar metabolites were glucuronoconjugates of 20-hydroxyecdysone. Acetylation of the conjugates followed by hydrolysis with glucuronidase gave a major labelled product: 20-hydroxyecdysone and minor peaks corresponding to a mixture of 20-hydroxyecdysone acetates. These results indicated that the 2,3,22,25-glucuronoconjugates of 20-hydroxyecdysone were the principal products in the inactivation process.