Leukotrienes and prostaglandins are both important classes of biomolecules that cells use for local signaling. Because both leukotrienes and prostaglandins play important roles in certain disease and pain processes, there are medications that help mediate their production and the metabolic pathways responsible for synthesis. Leukotrienes generally operate within the immune system, while prostaglandins have roles in inflammation and pain.
Leukotrienes
Leukotrienes, very generally, are communication and local signaling molecules that produce inflammation and activate the immune system. As such, they play an important role in the inflammatory processes that lie at the center of asthma and allergic response, particularly to airborne pollens and other airborne allergens. They act as cellular signaling agents, called chemotactic agents, which means that they draw immune cells--particularly neutrophils--toward the site of an invasion or perceived invasion, explains Dr. Lauralee Sherwood in her book "Human Physiology."
Leukotriene Metabolism
Metabolism refers to the sum of chemical reactions taking place in the body. Specifically, leukotriene metabolism is the process by which the body produces leukotrienes from precursor compounds. An enzyme produces leukotrienes from a compound called arachadonic acid, explain Drs. Reginald Garrett and Charles Grisham in their book "Biochemistry." Arachadonic acid is an omega-6 fatty acid. Its important role in leukotriene synthesis is one of the reasons that omega-6 fatty acids, while essential to life, are considered pro-inflammatory compounds.
Prostaglandins
Like leukotrienes, prostaglandins are local signaling molecules. They have a variety of effects upon the body, many of which relate to inflammation and the sensation of pain. In very general terms, prostaglandins are irritant compounds that increase the ability of the nervous system to sense pain and communicate that sensation to the brain. They also have a variety of other roles in the body--they help to produce the initiation of labor in delivering a baby, for instance.
Prostaglandin Metabolism
Enzymes called cyclooxygenases have crucial roles in the metabolism of prostaglandins. The cyclooxygenase enzymes, often called simply the COX enzymes, are therefore central to the sensation and perception of pain. They convert compounds called fatty acids, which are components of dietary fats, into prostaglandins by a series of chemical reactions. Many common analgesics, including aspirin and ibuprofen, are COX inhibitors, meaning that they block the production of prostaglandins by blocking the activity of the COX enzymes.
References
- "Human Physiology"; Lauralee Sherwood, Ph.D.; 2004
- "Biochemistry"; Reginald Garrett, Ph.D. and Charles Grisham, Ph.D.; 2007
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