Ecdysteroids biosynthesis

M. domestica oostatic hormone seems to Inhibit the release or synthesis of egg development neurosecretory hormone (EDNH) (12), but in mosquitoes the hormone seems to act directly on the ovary (6). R, prolixus oostatic hormone, which has been partially purified (13), is a small peptide of M, 1,411 as determined on Sephadex G-50. Kelly et al. (5) prepared a crude extract of oostatic hormone from M, domestica, injected it into the autogenous mosquito Aedes atropalpus, and demonstrated inhibition of both egg development and ecdysteroid biosynthesis. They suggested that oostatic hormone functions at a point subsequent to release of EDNH. They were unable, however, to exclude the possibility that release of EDNH, itself, was inhibited. 

The biosynthesis of ecdysteroids in filarial worms has been studied [75]. It has been shown that D. immitis and Brugia pahangi can not synthesize ecdysteroids from cholesterol. Further, no evidence was available to support the conversion of ecdysone (14) to 20-hydroxyecdysone (15). Not withstanding the fact that the basic studies regarding endocrinology of female worms are still not elaborate, interference of ecdysteroid biosynthesis and function in female helminths may provide... 

We will discuss some of our comparative sterol metabolism studies and provide specific examples to illustrate some of these unusual variations in steroid utilization and metabolism in insects, and to show how this information is useful in predicting differences in ecdysteroid biosynthesis in certain species. We will also point out instances in which these variations in neutral sterol metabolism can be related to phylogenetic relationships between species. 

Dell, S., Sedlmeier, D., Bocking, D., and Dauphin-Villemant, C. (1999) Ecdysteroid biosynthesis in crayfish Y-organs feedback regulation by circulating ecdysteroids. Arch. Insect Biochem. Physiol, 41, 148-155. 

Biosynthesis and ecdysteroid regulation of housefly sex pheromone production... 

Blomquist G. J., Adams T. S., Halamkar P. P., Gu P., Mackay M. E. and Brown L. (1992) Ecdysteroid induction of sex pheromone biosynthesis in the housefly, Musca domestica. Are other factors involved J. Insect Physiol. 38, 309-318. 

Wicker C. and Jallon J.-M. (1995a) Influence of ovary and ecdysteroids on pheromone biosynthesis in Drosophila melanogaster (Diptera, Drosophilidae). Fur. J. Entomol. 

Endocrine mediators, including specific pheromonotropins (e.g. pheromone biosynthesis activating neuropeptide [PBAN]) (reviewed in Raina, 1993 Nagasawa et al., 1994 Rafaeli, 2002 Rafaeli and Jurenka, Chapter 5, in this volume), JH (reviewed in Tillman et al., 1999), and ecdysteroids (reviewed in Blomquist et al., 1993 Blomquist, Chapter 8, in this volume), can regulate pheromone biosynthesis in different insect species. 

In addition to their well established role in catalyzing the metabolism of a wide variety of naturally occurring and synthetic xenobiotics, cytochrome P-450-mediated mixed-function oxidases are of critical Importance in the biosynthesis and regulation of the major hormones (ecdysteroids and juvenile hormone) that control insect growth and development. The characteristics of the mixed-function oxidases involved in the synthesis of insect hormones are described and the possibility that the enzymes might represent potential targets for insect control is discussed. 

Keywords biosynthesis cardiac glycosides ecdysteroids metabolic pathways phylogeny pregnanes saponins secondary metabolites withanolides... 

Adler, J.H. and Grebenok, R.J. (1999) Occurrence, biosynthesis, and putative role of ecdysteroids in plants. Crit. Rev. Biochem. Mol. Biol., 34,253-64. 

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