**5. Endothelin system**

The endothelin system is comprised of:


### **5.1 Endothelin-1**

Endothelin-1 was discovered as a potent vasoactive peptide [11] mainly secreted by endothelial cells and playing a role in regulating vascular tone, blood pressure, cell proliferation, and hormone production. It is now known to have diverse biological actions on almost all aspects of physiology and cell function and is increasingly being recognized as a pro-inflammatory cytokine. Because of its vasoconstricting effects on vascular smooth muscle cells (VSMCs) and the resultant increase in arterial blood pressure, the peptide is best known for its role in hypertension. It is a molecule with great clinical relevance with critical roles in neurological function [12], pulmonary physiology [13], chronic kidney disease [14], fluid and electrolyte transport [15], autoimmune disorders [16], cancer biology [17], inflammatory response and sepsis [18], embryogenesis [19, 20], and importantly endothelial dysfunction [21].

*An Overview of Gene Variants of Endothelin-1: A Critical Regulator of Endothelial Dysfunction DOI: http://dx.doi.org/10.5772/intechopen.108108*
