Endoteliinijärjestelmä

The endoteliinijärjestelmä, or the endothelin system, is a group of peptide hormones and their receptors that play a significant role in regulating cardiovascular function and other physiological processes. The primary active peptide in this system is endothelin-1 (ET-1), a potent vasoconstrictor. ET-1 is produced by endothelial cells, the inner lining of blood vessels, in response to various stimuli, including hypoxia and shear stress.

The endothelin system consists of three main endothelin peptides (ET-1, ET-2, and ET-3) and two types of G protein-coupled receptors, ETA and ETB. ETA receptors are primarily responsible for mediating the vasoconstrictive effects of endothelin, while ETB receptors have more complex roles, including promoting vasodilation through nitric oxide release and clearing endothelin peptides from circulation.

Dysregulation of the endothelin system has been implicated in the pathophysiology of several diseases, particularly cardiovascular conditions such as hypertension, pulmonary hypertension, atherosclerosis, and heart failure. Increased levels of endothelin-1 are often observed in these conditions, contributing to excessive vasoconstriction, smooth muscle cell proliferation, and inflammation. Consequently, endothelin receptor antagonists have been developed and are used clinically for the treatment of pulmonary arterial hypertension. The endothelin system also influences other functions, including cell growth, renal function, and neurotransmission, highlighting its broad physiological importance.