Juvenile Hormone


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Related to Juvenile Hormone: ecdysone

juvenile hormone

[′jü·vən·əl ′hȯr‚mōn]
(biochemistry)

Juvenile Hormone

 

an insect hormone that regulates the stage-by-stage development of insects. Chemically an isoprenoid, juvenile hormone is a colorless, optically active viscous oil that is insoluble in water.

It was discovered in 1956 by the American entomologist C. Williams in the abdomen of the male Hyalophora cecropia, a butterfly. Its isolation, structural determination, and chemical synthesis were first accomplished by a group of American scientists in the period 1967–69. The hormone occurs in insects with complete as well as incomplete metamorphosis. Its amount in the insect organism is very small, of the order of 10–1 to 10–2 μg/g.

Juvenile hormone is synthesized and secreted by the corpora allatum under the influence of the protein-activating hormone produced by the neurosecretory cells of the brain from the moment the larvae hatch from the ovum. During the larval period, it inhibits the activity of another hormone, ecdysone, which stimulates larval growth and hastens the molting of larva, thus contributing to the normal development of the larva to complete maturity. Inhibition is apparently effected through repression of the genes. With successive moltings, the secretion of juvenile hormone gradually decreases and is drastically reduced in the final larval stage, as a result of which the larva is transformed into a pupa under the influence of ecdysone. Thus, a balanced interaction of juvenile hormone and ecdysone ensures normal development in insects. Juvenile hormone also manifests gonadotrophic activity, influences diapause, and in some insects stimulates production of the sexual pheromones. Other isoprenoids, in particular juvabione, as well as many synthetic analogs, also possess the capability of juvenile hormone.

The use of juvenile hormone and its analogs as insecticides that disrupt the normal developing of insects has proved successful in controlling the larva of the cotton bollworm (Heliothis armígera) and other dangerous pests of agricultural and timber crops. The disadvantage of the insecticides is that their maximum effectiveness is only during the short period of the transformation of an immature individual into a mature one. Antagonists of juvenile hormone, called precocenes (from the English “precocious,” meaning early maturing), which cause premature metamorphosis of larvae, sterility, and anomalous diapause in insects, have been discovered in certain higher plants. Precocenes appear to be promising as “antihormonal” insecticides.

REFERENCES

Pridantseva, E. A., A. A. Drabkina, and Iu. S. Tsizin. “luvenil’nyi gormon nasekomykh.” Uspekhi sovremennoi biologii, 1971, vol. 71, issue 2.
Krimer, M. Z., and A. A. Shamshurin. Khimiia iuvenil’nogo gormona i ego analogov. Kishinev, 1972.
Röller, H., and K. H. Dahm. “The Chemistry and Biology of Juvenile Hormone.” In Recent Progress in Hormone Research, vol. 24. New York-London, 1968.
Naturally Occurring Insecticides. Edited by M. Jacobson and D.Crosby. New York, 1971.
Bowers, W. S., et al. “Discovery of Insect Anti-juvenile Hormones in Plants.” Science, 1976, vol. 193, no. 4253.

E. P. SEREBRIAKOV

References in periodicals archive ?
The three gene markers selected for the juvenile hormone signaling pathway (MET, SRC, and Hb2) increased their transcription levels in the presence of TBT just after molting at 0 hr and/or at 48 hr.
20-Hydroxyecdysone interacts with juvenile hormone and dopamine in the control of Drosophila virilis fertility.
The primary, and perhaps only, function of the corpus allatum is juvenile hormone synthesis.
Juvenile hormone mimics (JHMs) ZR512 (ethyl 3,7,11-tri-methyldodeca-2,4 dienoate) and ZR512 [isopropyl (2E,4E)-l1-methoxy-3,7,11-tri methyl-2,4-dodecadienoate] were dissolved in light mineral oil (Fisher, Saybolt viscosity 125/135) to give a final concentration of 20 [micro]g/[micro]l for each JHM.
Hormonal regulation and functional role of Drosophila E75A orphan nuclear receptor in the juvenile hormone signaling pathway.
The effect of juvenile hormone mimics on development of the mud crab Rhithropanopeus harrisii (Gould).
Washington, August 5 (ANI): A new study has demonstrated that programmed cell death - a process by which cells deliberately destroy themselves - is key to termite evolution wherein they molt from workers, to presoldiers and finally soldiers under the effect of juvenile hormones.
The researchers gave some of the fall butterflies a chemical that mimics juvenile hormone and then placed them in a flight simulator to see whether the hormone could block navigation.
Methyl farnesoate is structurally very similar to the insect terpenoid juvenile hormone III (Figure 1), which can activate ultraspiracle (Jones and Sharp 1997).
Flight muscle histolysis in the house cricket, Acheta domesticus, is induced by juvenile hormone (JH) and is an example of active programmed cell death that requires de novo protein synthesis.
MetaLarv S-PT contains the active ingredient (S)-methoprene, an insect juvenile hormone analog that prevents the development of mosquito larvae into the adult mosquito stage where certain species may be capable of transmitting harmful disease such as West Nile virus, malaria, dengue fever, and encephalitis.

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