Chemical Structure and Juvenile Hormone Activity

Abstract

JUVENILE hormone acts directly on individual cells of the insect and ensures the appearance and maintenance of those structural features which characterize the larval stage¹. Because this hormone is merely controlling the manifestation of certain genetically determined characters which are latent in the epidermal cells, I predicted that “it would be by no means impossible for a variety of chemical substances to exert such an effect—just as a wide variety of chemicals can exert an “anti-bar” effect in bar-eyed mutants of Drosophila”². It is, however, still unknown whether the site of action of the hormone is the cytoplasm or the nucleus. In a survey of the mode of action of growth hormones in insects I suggested that the juvenile hormone could be “concerned in the regulation of permeability relations within the cell—in such a way that the gene-controlled enzyme system responsible for larval characters is brought increasingly into action when the juvenile hormone is present”³.