Radiolabeled methyl farnesoate is epoxidized to juvenile hormone III by an NADPH-dependent reaction occurring in corpus allatum homogenates from the cockroach Blaberus giganteus L. Most of the enzymatically produced juvenile hormone has the 10R configuration described for previously isolated natural juvenile hormones. The unnatural 2Z geometrical isomer of methyl farnesoate is epoxidized by the above system faster than the natural 2E isomer. Several series of chemicals known to be inhibitors of mixed-function oxidases were surveyed as inhibitors of methyl farnesoate epoxidation. The anti-juvenile hormone precocene II caused negligible inhibition at 1 · 10-4 M, whereas the best inhibitor was o-bromophenoxymethyl-imidazole with an apparent I50 of 4 · 10-7 M. None of the inhibitors tested were potent morphogenetic agents on Tenebrio molitor pupae, and they failed to cause precocious development of Oncopeltus fasciatus nymphs. The inhibition of in vitro juvenile hormone biosynthesis suggests the possibility of finding an anti-hormone which acts by blocking juvenile hormone biosynthesis.
ASJC Scopus subject areas
- Agronomy and Crop Science