Pii: S0196-9781(01)00660-x

Retrocerebral complexes (RCs) were isolated from adult females of the moths Heliothis virescens and Manduca sexta. Different homologs of juvenile hormone (JH) produced by the isolated RCs were identified and amounts measured by capillary gas chromatographychemical ionization (isobutane)-mass spectroscopy. Only JH I, II and III were identified. Incubation of RCs from both species in media containing acetate, but no propionate, induced production of approximately equal amounts of JH II and JH III, but the amount of JH I present was very low in all samples. Incubation of RCs with synthetic Manduca sexta allatotropin stimulated significant increases in production of all three homologs but increases in JH I and JH II were greater than those for JH III. The effect of allatotropin was mimicked by addition of propionate to the medium, which indicated that allatotropin increased supply of acetyland propionyl-CoA precursors. Incubation of tissue from H. virescens females during the first 24 h after eclosion with synthetic Manduca sexta allatostatin did not reduce production of JH. However, incubation of tissue from 3-day-old females with allatostatin significantly reduced production of JH. Similarly, incubation of tissue from H. virescens females during the first 24 h after eclosion with both allatotropin and allatostatin did not increase JH over the amount present in extracts from tissue incubated without the neuropeptides, indicating that allatostatin negated the action of allatotropin. Incubation of tissue from H. virescens females with allatostatin plus farnesol or JH III acid resulted in significant production of JH III, but neither JH I nor JH II was detected. These findings indicated that allatostatin acts prior to formation of the sesquiterpene alcohol precursors of JH. © 2002 Published by Elsevier Science Inc.