eicosanoid

(noun)

Any of a family of naturally occurring substances derived from 20-carbon polyunsaturated fatty acids; includes prostaglandins, thromboxanes, leukotrienes, and epoxyeicosatrienoic acids; function as hormones.

Related Terms

Examples of eicosanoid in the following topics:

  • Eicosanoids

    • The networks of controls that depend upon eicosanoids are among the most complex in the human body.
    • Eicosanoids are derived from either omega-3 (ω-3) or omega-6 (ω-6) EFAs.
    • The ω-6 eicosanoids are generally pro-inflammatory; ω-3s are much less so.
    • Two families of enzymes catalyze EFA oxygenation to produce the eicosanoids:
    • Eicosanoids are not stored within cells; they are synthesized as required.

  • Prostaglandins

    • Because their genesis in body tissues is tied to the metabolism of the essential fatty acid arachadonic acid (5,8,11,14-eicosatetraenoic acid) they are classified as eicosanoids.
    • The metabolic pathways by which arachidonic acid is converted to the various eicosanoids are complex and will not be discussed here.

  • Chemistry of Hormones

    • Eicosanoids are also lipid hormones that are derived from fatty acids in the plasma membrane.
    • Unlike other hormones, eicosanoids are not stored in the cell—they are synthesized as required.

  • The Endocrine System

    • Hormones can be divided into four separate groups: amino acids, polypeptides and proteins, steroids, and eicosanoids.
    • The first three groups have hormones that can have a large impact psychologically; the eicosanoids primarily regulate blood movement.

  • Mechanisms of Hormone Action

    • Lipid: Steroid hormones that contain lipids synthesized from cholesterol and eicosanoids that contain lipids synthesized from the fatty acid chains of phospholipids found in the plasma membrane.