Endoteliini1ä

Endoteliini1ä is not a widely recognized term in standard biomedical nomenclature. The spelling resembles endothelin-1 (ET-1), a potent vasoactive peptide produced primarily by vascular endothelial cells. The trailing “ä” likely reflects a transliteration or typographical variant rather than a distinct molecule.

Endothelin-1 is synthesized as a precursor called preproendothelin-1, which is processed to proendothelin-1 and then to big endothelin-1. The Big ET-1 is converted by endothelin-converting enzymes (ECE-1 or ECE-2) into endothelin-1, a 21–amino-acid peptide with a very short circulating half-life. ET-1 exerts its effects primarily through two G protein–coupled receptors, ETA and ETB. ETA receptors, located mainly on vascular smooth muscle, promote vasoconstriction and cell proliferation. ETB receptors, found on endothelium and other cell types, can mediate vasodilation via release of nitric oxide and prostacyclin, and when located on smooth muscle can also contribute to vasoconstriction.

Physiological roles of ET-1 include regulation of vascular tone, blood pressure, and renal function, as well as participation in vascular remodeling and inflammatory responses. Dysregulation of the endothelin system is implicated in several diseases, notably pulmonary arterial hypertension (PAH) and systemic hypertension. Clinically, endothelin receptor antagonists are used to treat PAH: bosentan blocks both ETA and ETB, ambrisentan selectively targets ETA, and macitentan provides broad antagonism with favorable pharmacokinetics. Potential adverse effects include liver function abnormalities, edema, and teratogenic risks.

Discovery of endothelin-1 occurred in 1988, in studies identifying endothelium-derived vasoconstrictors, marking a milestone in understanding vascular biology.