BIOSYNTHESIS AND REGULATION OF JUVENILE-HORMONE-III, JUVENILE-HORMONE-III BISEPOXIDE, AND METHYL FARNESOATE DURING THE REPRODUCTIVE-CYCLE OF THE GREY FLESHFLY, NEOBELLIERIA (SARCOPHAGA) BULLATA

To study the effect of brain signals on the biosynthesis juvenile horm one by the corpora allata of the grey fleshfly Neobellieria bullata, e xposed corpora allata connected to the brain were surgically removed f rom sugar-fed flies and incubated in vitro with L-[H-3-methyl]methioni ne, After incubation, the media together with. the tissues were analyz ed by HPLC. [H-3]Juvenile hormone III (JH III), [H-3]JH III bisepoxide (EE), [H-3]methyl farnesoate (MF) and an unknown [H-3]labeled metabol ite (Un) were identified as the primary products. The rate of synthesi s of [H-3]JH PII bisepoxide was higher than that of [H-3]JH III, [H-3] MF and [H-3]Un. Two days after a liver meal, female flies synthesized more JH III, MF, BE, and the Un than did males. Synthesis of JH III, B E, and MF in females was lower during the previtellogenic, sugar-feedi ng period than during the vitellogenic liver-feeding period. Isolated corpus cardiacum-corpus allatum (CC-CA) complexes that were incubated in vitro synthesized less JH III, MF, and SE, as compared to complexes that were attached to the brain, indicating that the brain probably m odulates the biosynthesis of JH IPI, MF, and BE in the corpora allata. Upon incubation of brain-CCCA complexes with Neb-TMOF (10(-8) M), Neb -colloostatin (10(-8) M) ovarian, of brain extracts resulted in signif icant inhibition of JH III and BE biosynthesis ill the presence of ova rian extracts. These results indicate that allatostatin-like factors a re present in the ovary of the flesh fly. (C) 1998 Wiley-Liss, Inc.