Prothoracotrophic activity of compounds that mimic juvenile hormone

Abstract

Juvenile hormone-mimicking substances such as farnesol, farnesyl methyl ether, farnesyl diethylamine, nerolidol, and dodecyl methyl ether have prothoracotrophic activity and can activate the prothoracic glands of brainless, diapausing pupae of Antheraea polyphemus and Hyalophora cecropia (Lepidoptera, Saturniidae) and cause them to initiate adult development. Such brainless pupae ordinarily remain in diapause for two years without developing. In certain solvent systems several of the agents tested had both prothoracotrophic and juvenile hormone activities, whereas in other solvent systems only prothoracotrophic activity. The reasons for this phenomenon were examined and the importance of the solvent system in applying these agents is discussed. Compounds with the most juvenile hormone activity were also the most potent prothoracotrophic agents and vice versa. Evidence from other laboratories indicates that compounds with greatest juvenile hormone activity also had greatest gonadotrophic activity. Hence all three activities appear to go together. Lipid extracts of cecropia moths also have juvenile hormone, prothoracotrophic and gonadotrophic activities. The present experiments show that the corpora allata are the source of at least two of these three activities. The present data suggest that the hormone secreted by the corpus allatum, the juvenile hormone, is a single chemical agent possessing morphogenetic, prothoracotrophic, and gonadotrophic activities and that the primary physiological action of juvenile hormone is the same in promoting all three activities. A possible role for juvenile hormone in stimulating the prothoracic glands of some Lepidoptera during larval life is discussed.