Hormonal control of molting in decapod crustacea

Abstract

The involvement of the molting hormone, 20-hydroxyecdysone, in the mediation of molting in decapod crustaceans is briefly reviewed. Aspects of the secretion and metabolism of its precursor, ecdysone, are discussed. Experiments are described that demonstrate the presence of a molt-inhibiting hormone (MIH) in the sinus glands of juvenile lobsters (Homarus americanus). Assays for MIH include measurement of the molt interval and radioimmunoassay of circulating titers of ecdysteroids in eyestalk-ablated lobsters. This latter assay indicates that sinus gland extracts significantly decrease the concentration of circulating ecdysteroids 24 hr after injection. Data are also presented on the circulating titers of ecdysteroids during multiple molt cycles of lobsters following eyestalk ablation. These data indicate that there must be another factor that ultimately regulates the circulating levels of the molting hormone. © 1985 the American Society of Zoologists.