Prostaglandins are a type of hormone, and they have many effects on the body. There are over a dozen different kinds of prostaglandins, with each having their own physiological function. Not only are prostaglandins involved in inflammation and blood clotting, they can also affect the kidneys and the digestive tract. Prostaglandins are a target of some pain-relieving drugs, including aspirin.
History
Prostaglandins were first identified, according to Elmhurst's Virtual Chembook, in human semen in the 1930s by the Swedish scientist Ulf von Euler. Von Euler believed, incorrectly, that these chemicals were made only by the prostate, and as a result he named them prostaglandins. It wasn't until much later that researchers discovered that many tissues make prostaglandins.
Structure
Prostaglandins are carboxylic acids, Elmhurst's Virtual Chembook explains, which means that they are made up of a carbon backbone with a carboxylic group on one end. These compounds have one or more carbon-carbon double bonds, which means that their chemical structure has occasional bends in it. Prostaglandins are made from a naturally occurring compound called arachidonic acid.
Inflammation and Fever
Prostaglandins are an important chemical in the body's inflammatory response, Dispirin explains. When tissue within the body is damaged, white blood cells flock to the site of injury and release several different prostaglandins. These prostaglandins can stimulate the production of a chemical called bradykinin, which is responsible for generating the pain signal. Prostaglandins also sensitize blood vessels to a chemical called histamine, which causes blood vessels to dilate, which leads to redness and swelling. Prostaglandins are also necessary for the generation of a fever. These chemicals, which are secreted in response to an infection, act on the hypothalamus, which controls the temperature of the body. When stimulated by prostaglandins, the hypothalamus raises the temperature of the entire body, causing a fever.
Other Effects
Prostaglandins also have other roles within the body, Elmhurst's Virtual Chembook explains. One kind of prostaglandin, called thromboxane, is important for the formation of blood clots. Thromboxane causes blood vessels to narrow and also causes platelets to stick together, which helps start the clotting process. Some prostaglandins induce labor during pregnancy; synthetic versions of these can be used to stimulate a pregnant woman to go into labor. Prostaglandins can also increase the flow of blood to the kidneys or inhibit acid production in the stomach.
Pain Relief
Aspirin and other pain medications, such as acetaminophen and COX-2 inhibitors, work by interfering with prostaglandin synthesis. These drugs block the cyclooxygenase enzyme, which is essential for the production of prostaglandins. The blockage of prostaglandins thus works to help reduce inflammation, pain and fever.
