内皮素1（ET-1）是从培养的猪主动脉内皮细胞上清液中，分离获得的1种具有强烈收缩血管作用的活性肽。内皮素1已被证明存在于许多哺乳动物中，包括人类。虽然血管内皮细胞是内皮素1的主要来源，但心肌细胞、血管平滑肌细胞、肾小管上皮细胞和神经胶质细胞等均可产生，提示内皮素1可以独立参与各种器官的复杂调节机制。
ETA and ETB
Endothelin-1 (ET-1) is a potent endogenous vasoconstrictor, mainly secreted by endothelial cells. It acts through two types of receptors: ETA and ETB. Apart from a vasoconstrictive action, ET-1 causes fibrosis of the vascular cells and stimulates production of reactive oxygen species. It is claimed that ET-1 induces proinflammatory mechanisms, increasing superoxide anion production and cytokine secretion.