Eicosanoids

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As eicosanoids (v. Greek είκοσι., Twenty), and eicosanoids , a group of hydrophobic , hormone-like refers to substances consisting of polyunsaturated fatty acids were formed. They can act as intra- and extracellular signal molecules and are involved in a large number of biological mechanisms of action. Although the term eicosanoids indicates a number of 20 carbon atoms in the molecule, the eicosanoids also include derivatives of other fatty acids that are shorter or longer chain, for example the derivatives of docosahexaenoic acid and linoleic acid .

Formation of the eicosanoids

Polyunsaturated fatty acids are the starting materials for eicosanoids. They can only be formed by the human body to a very limited extent. They are ingested directly with food and function primarily as components of cellular membranes, where they are mainly found in phospholipids . An extracellular signal can activate phospholipases and release fatty acids from the membranes. This makes the fatty acids accessible to enzymes that form the eicosanoids through oxidation reactions ( epoxidation or hydroxylation ) or rearrangement reactions. As a result of several reaction steps and intermediate products, numerous different compounds result, with the number of carbon atoms in the molecule remaining constant.

Structural formula of prostanoic acid
Structural formula of 14,15-EET

The oxidation is mediated in four different ways and results in different groups of substances:

Biological effect

Eicosanoids are intra- and extracellular signaling substances that can be produced by every cell and usually act via G-protein-coupled membrane receptors . However, the exact mechanism of action has not yet been clarified , especially in the case of the eicosanoids formed by CYPs . Eicosanoids are involved in the regulation of inflammatory reactions such as fever and allergy . They play an important role in regulating the cardiovascular system , blood pressure , salt excretion, blood clotting and pain . Neuronal diseases such as Alzheimer's and depression , as well as the development of tumors , are also influenced by eicosanoids. The health-promoting effect attributed to omega-3 fatty acids is due to the eicosanoids formed from them, which is why these fatty acids are often referred to as good fatty acids. From omega-6 fatty acids , however, eicosanoids are formed, the more undesirable properties ( proinflammatory , vasoconstrictive , carcinogenic ). However, there are also eicosanoids formed from omega-6 fatty acids that have the opposite effect, for example 14,15-EET.

literature

  • J. Szefel, WJ Kruszewski, E. Sobczak: Factors influencing the eicosanoids synthesis in vivo. In: BioMed research international. Volume 2015, 2015, p. 690692, doi : 10.1155 / 2015/690692 , PMID 25861641 , PMC 4377373 (free full text).
  • M. Puppolo, D. Varma, SA Jansen: A review of analytical methods for eicosanoids in brain tissue. In: Journal of chromatography. B, Analytical Technologies in the Biomedical and Life Sciences. Volume 964, August 2014, pp. 50-64, doi : 10.1016 / j.jchromb.2014.03.007 , PMID 24685838 .