Your endothelium, which lines your blood vessels, makes endothelin. This peptide, or small protein, helps regulate blood pressure by constricting blood vessels. When you make too much endothelin, you may develop high blood pressure, as well as heart and lung issues. Endothelin receptor antagonists can lower endothelin levels in your blood.
Endothelin (ET) is a peptide (small protein) that helps regulate your blood pressure by constricting (tightening) your blood vessels. Peptides are small proteins made up of short chains of amino acids (organic compounds). Your endothelium (the cells lining the inside of your blood vessels) makes endothelin. This smaller protein serves as a building block for larger proteins in your body.
Your endothelium is a thin layer of endothelial cells that line the inside of your blood vessels. It is your body’s largest organ. Endothelial cells release substances that control vascular tone, or the opening (dilation) and closing (constriction) of arteries. Vascular tone determines how hard your heart works to pump blood and circulate it through your body.
The endothelium and endothelin also:
Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy
Endothelins are your body’s most powerful vasoconstrictor. Vasoconstriction increases your blood pressure. To break it down:
Elevated levels of endothelin can cause conditions that damage your heart and lungs. These conditions include:
Medical researchers first identified endothelins in 1987. Four different amino acid peptides make up three types of endothelins, which are all vasoconstrictors. The most common and strongest endothelin in your body is endothelin-1 (ET-1). Researchers are still learning how the ET-2 and ET-3 types affect your body.
All tissues have endothelin receptors. These receptors bind to endothelins, helping them communicate with cells throughout your body.
A blood test measures ET-1 in plasma. Plasma is the liquid part of your blood that remains after a lab removes platelets and white and red blood cells. A blood test may take place in your healthcare provider’s office, a hospital or a lab. Blood tests are unable to detect the other types of endothelins.
Healthcare providers measure endothelin in picograms per milliliter (pg/mL). In adults, a normal ET-1 plasma level is 1 pg/mL to 2 pg/mL. ET-1 levels are higher in children. These levels also vary among different races.
Elevated ET-1 levels are found in certain heart or lung conditions such as pulmonary arterial hypertension. Certain heart procedures like balloon angioplasty can raise endothelin levels.
Endothelin receptor antagonists (ERA) are medications that lower the amount of endothelin in your body. They’re a type of targeted therapy, which means they identify and attack certain problem cells without damaging healthy ones. ERAs are used in the treatment of certain types of pulmonary arterial hypertension.
Females who are pregnant or planning to become pregnant shouldn’t take ERAs because the drugs can cause birth defects.
In rare instances, the medications can damage your liver. Your healthcare provider may order more frequent blood tests to monitor the health of your liver.
Other potential side effects of ERAs include:
A note from Cleveland Clinic
Endothelin helps regulate your blood pressure by constricting your blood vessels. When your endothelin levels get too high, your blood vessels constrict more than they should. This can lead to blood pressure problems, as well as heart and lung conditions. You may need to take endothelin receptor antagonists (ERAs) to lower the amount of endothelin in your blood. A blood test checks endothelin levels in plasma.
Last reviewed by a Cleveland Clinic medical professional on 05/12/2022.
Learn more about our editorial process.
Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy