Corpus allatum

Evans, L. D. and Stay, B. (1995). Regulation of competence for milk production in Diploptera punctata interaction between mating, ovaries and the corpus allatum. Invertebrate Reproduction and Development 28 161-170. 

Smith, A. F. and Schal, C. (1990a). Corpus allatum control of sex pheromone production and calling in the female brown-banded cockroach, Supella longipalpa (F.) (Dictyoptera Blattellidae). Journal of Insect Physiology 36 251-257. 

Chiang A.-S., Gadot M., Burns E. L. and Schal C. (1991) Developmental regulation of juvenile hormone synthesis ovarian synchronization of volumetric changes in corpus allatum cells in cockroaches. Molec. Cell. Endocrinol. 75, 141-147. 

Alternatively, a product of the developing ovary could initiate pheromone production. JH was ruled out because removal of the corpus allatum-corpus cardiacum within 6 h of eclosion did not inhibit the production of (Z)-9-tricosene. In contrast, flies overiectomized within 6 h of emergence do not produce detectable amounts of any of the C23 pheromone components (Dillwith et al., 1983). When ovariectomized flies received ovary implants from 24-h-old donors on day 4, C23 sex pheromone components were detected three days later. Housefly ovaries have been shown to produce ecdysteroids (Adams et al., 1997). 

These inhibitors would be classified as anti-juvenile hormones and could be expected to show selective action on insects as a class. Such analogs are by no means just around the corner since at least two important properties that they should possess may be difficult to build into small organic molecules suitable for pest control. These properties are the ability to withstand general metabolic inactivation while retaining the ability to inhibit irreversibly the target enzymes of the corpus allatum and the property to accumulate selectively in corpora allata, a physically small target, so as to offset dilution in the general body cavity. 

A major step forward, which extended our understanding of the range of neuropeptide activities, occurred after the advent of electron microscopy. The observation of synapse-like ("synaptoid") contacts between peptidergic neuron terminals and endocrine cells (in the corpus allatum as well as the adenohypophysis) clearly indicated that close-range signals from neural to endocrine cells contribute to the process of neuroendocrine communication. Subsequently, such peptidergic contacts turned out not to be restricted to endocrine cells they also occur on various somatic cells. 

Precocenes induce precocious metamorphosis by causing irreversible changes in the development of the coipus alla-tum, a vital hormone-producing gland in insects. Treatment with juvenile hormone (produced by the corpus allatum) temporarily reverses the effects of precocenes (Bowers, 1988,1991,1992). Precocenes first are absorbed in the insect fat body. The use of this group of hemiterpenes for insecticidal purposes is limited, however, because of the specificity of action. Many insects are able to detoxify and excrete precocenes rapidly (Bowers, 1988, 1991). When precocene 2 (14) was fed to the grasshopper, Melanoplus sanguinipes, it was converted to the 2-hydroxymethyl derivative and a demethylated product. These oxidized products are less toxic than the parental compounds and are more readily excreted (Harbome, 1989). 

---