Prostaglandins and leukotrienes

Prostaglandins are molecules that behave like hormones and are used for signaling between cells. They are produced by many cell types and tissues in the body.

To make prostaglandins, an enzyme called phospholipase A2 turns diacylglycerol into arachidonic acid (AA). All prostaglandins are derived from AA and this molecule is mentioned often in scientific literature about mast cells, as it is easier to detect AA than some prostaglandins. Once AA has been produced, one of two things happen: AA is either changed by the cyclooxygenase (COX) pathway into prostaglandins and thromboxanes or by the lipoxygenase (LO) pathway into leukotrienes.

Prostaglandins, thromboxanes and leukotrienes are all types of eicosanoids. Eicosanoid is another common word in mast cell literature, and in that context it usually refers to prostaglandins or leukotrienes.

To make prostaglandins from AA, cells use the enzymes COX-1 and COX-2. COX-1 produces regular low levels of prostaglandins, whereas COX-2 makes prostaglandins in response to inflammation. Other enzymes called prostaglandin synthases finish off making the prostaglandins into the right shapes. To make leukotrienes from AA, cells use the enzyme arachidonate 5-lipoxygenase.

There are a number of medications that interfere with the production of leukotrienes or prostaglandins by interfering with the enzymes that make them. This is generally regarded as a more effective way to treat symptoms from these products, rather than trying to block their action after they have been made.

Non steroidal anti-inflammatories (NSAIDs), of which there are dozens, interfere with the activity of both COX-1 and COX-2. Newer COX-2 inhibitors like Celebrex only inhibit COX-2. Vitamin D downregulates expression of COX-2. A chemical in St. John’s Wort is also a COX-1 inhibitor. Zileuton is a lipoxygenase inhibitor.

5 Responses

  1. Karen Neill April 25, 2015 / 2:15 pm

    Lisa, could you make the connection from these prostaglandins and leukotrienes to symptomatology? I’m missing a couple steps…
    As always, very helpful info.

    • Lisa Klimas April 25, 2015 / 6:01 pm

      Yes, I’m going to do a post on the symptoms associated with them.

  2. Ellen Beato April 26, 2015 / 8:08 pm

    I missed whatever happened and am sorry to see you were hurt by someone. I greatly appreciate all the help you have given us, especially being so sick yourself. If anyone should understand that, it should be this group. I have said I would pray for you and am very sorry if that offended you. I am the first to say that everyone has the right to their own beliefs and religions. I never try to convert anyone. I hope you will be able to come back, and that those that hurt you will back off. You are precious to us. I have learned more from you than any of the “experts”. My background is also science- in nursing and then special education, and I understand exactly where you are coming from.

    • Lisa Klimas April 26, 2015 / 10:04 pm

      Thank you. I have been really touched by messages of support and people standing up for me. You guys are great. I need to put some infrastructure in place so that when things like this happen, I am not the only one who can respond. This is a failing on my part in that I have known I needed to do it and haven’t gotten around to it. I will be back. I’m not going anywhere, just need a few days to refresh. Thanks again!

  3. Mia February 5, 2016 / 11:10 am

    I am struggling with sleeping disorders. I have Mast Cell Disease and I have medication for that but nothing seems to help me sleep better. If I understood your post correctly, PGD2 also regulates sleep. Maybe it is useful for me to try St. John’s Wort to sleep better? This post gave me a lot of new information, thank you for that!

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