Ecdysteroids during the development of the tsetse fly

Abstract

Summary The data presented here document the variations of ecdysteroids in different tissues during the life-span of the tsetse fly. HPLC analyses were performed to determine the nature of immunoreactive compounds detected by RIA. In milk glands, uterus and ovaries at the beginning of vitellogenesis, 20-hydroxyecdysone appeared as the main free ecdysteroid. However, conjugation occurred in mature ovaries where 85% of the immunoreactivity was found in highly polar fractions. During embryogenesis and larval development, the ecdysteroids detected in crude extracts mainly corresponded to polar or apolar metabolites. The nature of the high polarity products differed between adult tissues and developing flies. Similarly the apolar compounds, unchanged after hog liver esterase action in the 3rd larval instar, could liberate some free ecdysone and 20-hydroxyecdysone together with polar and unknown compounds especially in mature ovaries. In the hemolymph collected either during vitellogenesis or just before larvip...