Response of cultured Aedes aegypti fat bodies to 20-hydroxyecdysone

Abstract

Fat bodies from non-blood-fed Aedes aegypti, stimulated in vitro by 10 −4 M and 10 −6 M of 20-hydroxyecdysone, were found to synthesize and release vitellogenin into the culture medium. Vitellogenin-specific monoclonal antibodies were utilized in an enzyme-linked immunosorbent assay procedure for quantification of vitellogenin in small aliquots of medium taken periodically from the culture. A minimal exposure of 5 h to 20-hydroxyecdysone was shown to be needed before the fat bodies would respond. Time-course of vitellogenin production in vitro was found to be identical to that observed in vivo. Vitellogenin-titre profiles were also investigated in cultured fat bodies from blood-fed A. aegypti. In all cases, response patterns were not affected by the presence or absence of 20-hydroxyecdysone after the fat bodies had been stimulated by blood meal to produce vitellogenin. We suggest here that initiation and control of vitellogenin synthesis is a programmed response to 20-hydroxyecdysone.