Crustecdysone (20-hydroxyecdysone): site of storage in the crayfish Orconectes propinquus

Abstract

Crustecdysone is found in crayfish at all stages of the molting cycle except during anecdysis. Ecdysone can only be detected from late proecdysis through ecdysis into early metecdysis, and its biological activity never reached a 10th of that of crustecdysone. No activity could be detected at any time in the brain, the eyestalks, or the mandibular gland. At all stages (except anecdysis) a gland which is situated in the antennary segment contained active material, with a maximum in late proecdysis. At that time the total activity in the blood was higher than in the gland, and some activity could be detected in the rest of the body, perhaps in undrained blood.