Novel assay for determining the metabolic fate of juvenile hormone III: A study with Drosophila melanogaster

A thin‐layer chromatographic assay was developed for the resolution of hydrolytic and conjugative catabolites of juvenile hormone (JH). A single‐dimension, dual‐development thin‐layer system allowed complete resolution of the catabolites. Thus, this system provided a means for the rapid and economic analysis of JH hydrolysis even when different hydrolytic activities were present concurrently. Purified hydrolytic enzymes were found to be superior to chemical methods for the generation of small amounts of standards of JH catabolites. The relative levels of activities of an epoxide hydrolase and an esterase toward JH III were found to be similar in microsomal preparations from three lines of adult Drosophila melanogaster isolated from a field population. However, selection of flies by exposure to cut orange resulted in the elevation of levels of epoxide hydrolase activities, whereas esterase levels were not affected to the same extent. The formation of the JH acid‐diol was not detected under the conditions of this study, suggesting that the JH acid and diol were not good substrates for epoxide hydrolase and juvenile hormone esterase, respectively.