Functions of the kidney 7: making prostaglandins
What are prostaglandins? What do prostaglandins have to do with the kidney? How might aspirin damage your kidney? Read this article to find out.
What are prostaglandins?
Prostaglandins are a lipid (fat) found in every tissue in the body. They are created from a substance called arachidonic acid through the action of an enzyme (protein) called cyclooxygenase (COX).
There are many different types of prostaglandins, which have a variety of functions in the body. Often the function of one prostaglandin will be the opposite of another prostaglandin.
Examples of this are:
- Opening and closing the airways
- Dilating and narrowing blood vessels (this alters how much blood can flow through them)
- Forming blood clots or breaking them up.
Prostaglandins are made where they’re needed in the body, rather than by one specific organ or gland. This means that if an organ is damaged, it may not be able to make prostaglandins and cannot access them from elsewhere.
Some prostaglandins can travel short distances and act as a hormone. A hormone is simply a chemical the body makes to send a signal to another part of the body. Think of them as a bit like a letter with instructions for their target.
Click here to learn more about prostaglandins.
What are the kidneys?
The kidneys are organs shaped like kidney beans, located in your back. They are found either side of your backbone. Most people have two kidneys, however some people may only have one. It is possible to live a normal, healthy and active life with just one kidney.
The kidneys are very important organs which help to remove water and waste materials from our bodies. However, they have several other important functions. The function that is going to be covered in this article is the role the kidneys play in making prostaglandins. Click here to learn more about the other functions of the kidney.
What are the prostaglandins the kidney makes?
The kidneys make many different types of prostaglandins. The most well-known are prostaglandin E2 (PGE2) and prostaglandin I2 (PGI2 – also known as prostacyclin). These are both ‘vasodilatory prostaglandins’.
This means they act on blood vessels to make them dilate (widen). This increases the volume of blood that can flow through the blood vessels. The action of these prostaglandins increases the blood flow to the kidneys. This in turn increases the blood supply to the filtering units of the kidney – the glomeruli.
All of this leads to an increased glomerular filtration rate (GFR), which is important for a healthy kidney. If there’s less blood flowing to the kidneys, the action of these prostaglandins can help compensate for that through the actions described above.
Click here to learn more about the functions of the kidneys.
What’s the link between prostaglandins and damage to the kidney?
The kidneys can be damaged by several drugs. One of these drug groups is called ‘non-steroidal anti-inflammatories’ or NSAIDs. This includes several well-known and common drugs such as aspirin and ibuprofen. NSAIDs damage the kidney by reducing the production of prostaglandins. They do this by inhibiting the COX enzymes, stopping them from converting arachidonic acid into prostaglandins.
This reduces the vasodilation (widening) of the blood vessels supplying the kidneys. As the blood vessels are narrower, less blood is able to go to the kidney (see above) which leads to it being damaged. This damage can present with an acute kidney injury (AKI) episode.
To prevent damage to the kidneys it’s important to always take medication as directed by your doctor and the package instructions. NSAIDS should only be taken for short periods, say 2-3 days 7 days maximum. [“One of the authors of this website has seen a patient’s kidney transplant stop working after taking ONE aspirin tablet. Fortunately, eventually, it got going again.” CKDEx]
If you already have damage to your kidneys (e.g. CKD) then, by and large, you shouldn’t take NSAIDs. Ask your doctor for more information.
Summary
We have described ‘functions of the kidney: making prostaglandins’. We hope it has been helpful.
Other resources
Functions of kidneys 1: waste removal
Functions of kidney 2: fluid balance (also affects blood pressure)
Functions of kidney 3: acid-base balance
Functions of kidneys 4: blood pressure control (makes renin)
Functions of kidneys 5: anaemia, blood cells and EPO (makes erythropoietin)
Functions of kidneys 6: vitamin D activation (activates cholecalciferol).
Watch this video to learn more about NSAIDs and kidney damage.
https://www.youtube.com/watch?v=KOEqrN56QV0
Last Reviewed on 10 March 2024