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Encyclopedia > Leukotrienes

Leukotrienes are autocrine and paracrine eicosanoid lipid mediators derived from arachidonic acid by 5-lipoxygenase. Autocrine signalling is a form of signalling in which the target cell is the secretory cell itself. ... Paracrine signalling is a form of signalling in which the target cell is close to the signal releasing cell, and the signal chemical is broken down too quickly to be carried to other parts of the body. ... In biochemistry, eicosanoids are a class of oxygenated hydrophobic cytokines that largely function as a autocrine and paracrine mediators. ... Arachidonic acid is a polyunsaturated fatty acid with four cis double bonds, which are the sources of its flexibility and give it the capacity to react with molecular oxygen. ...

Contents


History and name

The name leukotriene comes from the words leukocyte and triene (a compound with three double bonds). What would be later named leukotriene C, "slow reaction smooth muscle-stimulating substance" (SRS) was originally described in 1938 by Feldberg and Kellaway. The researchers isolated SRS from lung tissue after a prolonged period following exposure to snake venom and histamine. White Blood Cells is also the name of a White Stripes album. ... Histamine is a biogenic amine chemical involved in local immune responses as well at regulating physiological function in the gut and acting as a neurotransmitter. ...


Biochemistry

Synthesis

Leukotrienes are synthesized in the cell from arachidonic acid by 5-lipoxygenase. The lipoxygenase pathway is active in leukocytes and in macrophages and synthesizes leukotrines. Arachidonic acid is a polyunsaturated fatty acid with four cis double bonds, which are the sources of its flexibility and give it the capacity to react with molecular oxygen. ... White Blood Cells is also the name of a White Stripes album. ... Macrophages (Greek: big eaters) are cells found in tissues that are responsible for phagocytosis of pathogens, dead cells and cellular debris. ...


Function

Leukotrienes act principally on a subfamily of G protein coupled receptors. They may also act upon peroxisome proliferator-activated receptors. Leukotrienes are involved in asthmatic and allergic reactions and act to sustain inflammatory reactions; several leukotriene antagonists are used to treat asthma. In cell biology, G-protein-coupled receptors, also known as GPCR, seven transmembrane receptors, heptahelical receptors, or 7TM receptors, are a class of transmembrane receptors. ... In cell biology, peroxisome proliferator-activated receptors (PPARs) are a group of nuclear receptor isoforms that exist across biology. ...


Leukotrienes, are very important agents in the inflammatory response. Some such as LTB4 have a chemotactic effect on migrating neutrophils, and as such help to bring the necessary cells to the tissue. Leukotrienes also have a powerful effect in vasoconstriction particularly of venules and of bronchoconstriction, they also increase vascular permeability. Examples of leukotrienes are LTB4 LTC4 LTD4 and LTE4.


See also

A chemical synthesis of Leukotriene A methyl ester The Wittig reaction is a chemical reaction of an aldehyde or ketone with a phosphonium ylide to give an alkene and triphenylphosphine oxide. ...


  Results from FactBites:
 
Leukotriene - Wikipedia, the free encyclopedia (694 words)
Leukotrienes are autocrine and paracrine eicosanoid lipid mediators derived from arachidonic acid by 5-lipoxygenase.
Leukotrienes are synthesized in the cell from arachidonic acid by 5-lipoxygenase.
Leukotrienes are involved in asthmatic and allergic reactions and act to sustain inflammatory reactions; several leukotriene antagonists are used to treat asthma.
  More results at FactBites »

 
 

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