Ecdysone is a prohormone of the major insect moulting hormone 20-hydroxyecdysone, which is secreted from the prothoracic glands. Insect moulting hormones (ecdysone and its homologues) are generally called ecdysteroids. Ecdysteroids act as moulting hormones of arthropods but also occur in other invertebrates where they can play different role.
