The Precocene Antijuvenile Hormones (Allatotoxins): A Case History in Insect Toxicology
The precocenes (ageratochromenes) have attracted attention as the first examples of simple molecules, superficially dissimilar in structure to the natural juvenile hormones (JHs) yet able to elicit remarkable JH-antagonistic effects in some species of insects. Precocenes appear to exert a cytotoxic action on the corpora allata (CA), mediated by an oxidative bioactivation in vivo. Reactive epoxide formation in the CA is the mechanism that currently best explains the results of several radiochromatographically based metabolism studies in precocene-sensitive insects. Other oxidatively derived reactive intermediates such as quinone-methides or oxyradicals have been suggested but these mechanisms await substantiation. The limited pharmacokinetic studies on precocenes conducted so far have not revealed differences that convincingly explain their species selectivity but methods must be found to maintain the bioavailability of parent precocenes to the CA for longer periods, especially in the seemingly insensitive larvae of lepidoptera.
KeywordsJuvenile Hormone Corpus Allata Corpus Allata Piperonyl Butoxide Diethyl Maleate
Unable to display preview. Download preview PDF.
- 5.W. S. Bowers, Anti-juvenile hormones from plants: chemistry and biological activity, Ponttficiae Academiae Scientiarum Scripta Varia, 41:129–156 (1977).Google Scholar
- 7.G. T. Brooks, A F. Hamnett, R C. Jennings, A. P. Ottridge and G. E. Pratt, Aspects of the mode of action of precocenes on milkweed bugs (O.fasciatus) and locusts (L. migratoria), Proceedings of the 1979 British Crop Protection Conference — Pests and Diseases, 1:273–279(1979).Google Scholar
- 10.G. E. Pratt, R. C. Jennings and A. F. Hamnett, The mode of action of precocenes, Scientific Papers of the Institute of Organic and Physical Chemistry of Wroclaw Technical University, No. 22, Part 1:347–356 (1981).Google Scholar
- 18.D. M. Soderlund, M. F. Feldlaufer, S. Y. Takahashi and W. S. Bowers, Mechanisms of selectivity in the action of precocenes, in: “Juvenile Hormone Biochemistry”, G. E. Pratt and G. T. Brooks, eds., Elsevier/North Holland, Amsterdam, pp 353–362 (1981).Google Scholar
- 19.R. C. Jennings and A. P. Ottridge, The synthesis of precocene-I epoxide, J. Chem. Soc. Chem Comm., 920–921 (1979).Google Scholar
- 25.S. Orrenius, H. Thor, D. Dimonte, G. Bellomo, P. Nicotera, D. Ross and M. T. Smith, Mechanisms of oxidative cell injury studied in intact cells, in: “Microsomes and Drug Oxidations”, A. R. Boobis, J. Caldwell, F. De Matteis and C. R. Elcombe, eds., Taylor & Francis, London, pp 238–247 (1985).Google Scholar