- Allatostatin
Allatostatins are
neuropeptide hormone s ininsect s andcrustacea . They have a twofold function: they both inhibit the generation ofjuvenile hormone [cite journal |author=Stay B, Tobe SS |title=The role of allatostatins in juvenile hormone synthesis in insects and crustaceans |journal=Annu. Rev. Entomol. |volume=52 |issue= |pages=277–99 |year=2007 |pmid=16968202 |doi=10.1146/annurev.ento.51.110104.151050] and reduce their food intake. They are therefore putative targets for insecticide research [cite journal |author=Gäde G, Goldsworthy GJ |title=Insect peptide hormones: a selective review of their physiology and potential application for pest control |journal=Pest Manag. Sci. |volume=59 |issue=10 |pages=1063–75 |year=2003 |pmid=14561063 |doi=10.1002/ps.755] .Types of Allatostatin
Three biochemically distinct types of Allatostatin have been described: A, B and C. Although originally identified in different insects, all three types are found in the fruitfly, Drosophila. These types of Allatostatin are not normally found in the same neurons, and so probably have different roles.
Control of food intake
Allatostatin is found in the cells in a small neuronal cluster, the frontal ganglion. It is also present in the axons which leave the frontal ganglion and run across the surface of the gut. Application of low concentrations of Allatostatin inhibit the spontaneous contractions of the gut. All three forms of Allatostatin appear to inhibit gut motility in all the insects which have been tested.
Interaction with Juvenile hormone
Juvenile hormone is synthesised in the corpora allata. In every insect tested, at least one of the three types of Allatostatin inhibits the biosynthesis of juvenile hormone. This is achieved by
paracrine release of Allatostatin from neurons in the brain which terminate in the corpora allata. The signal is transduced byGPCR receptors, but the intracellular pathway is not yet known. Otheramine andneuropeptide neurotransmitters may also inhibit juvenile hormone biosynthesis.References
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