INVITRO ASSAY FOR THE BIOSYNTHESIS AND METABOLISM OF JUVENILE-HORMONE BY EXPOSED CORPORA ALLATA OF AEDES-AEGYPTI (DIPTERA, CULICIDAE)

A technique has been developed to study JH III biosynthesis in vitro by removing the head and thorax of Aedes aegypti (L.) and exposing the corpora allata (CA). Exposed CA were incubated with [12-H-3]methyl farnesoate, and the newly synthesized JH III and JH III metabolites were followed using C18 reversed-phase, high-performance liquid chromatography (HPLC) and preparative gas chromatography. The rate of synthesis of [12-H-3]JH III by exposed CA from newly emerged adult Ae. aegypti was 23 fmol/CA/h. The rate of synthesis of [12-H-3]JH III decreased 4-fold 3 d after adult eclosion and increased to 23 fmol/CA/h 5 h after the blood meal. Exposed CA of blood-fed and sugar-fed Ae. Aegypti were also incubated with L-[methyl-H-3]methionine, and the rate of synthesis of JH III was studied. The rate of JH III biosynthesis increased immediately after the blood meal as was found with (12-H-3]methyl farnesoate. The potential application of methyl farnesoate in monitoring the de novo synthesis of JH III in mosquitoes in vitro and in vivo is discussed.