Endothelins are endothelium-derived vasoconstrictor peptides. Expressed in various organs including heart, lung, liver, kidney, gastrointestinal tract, uterus and ovary, but not in spleen. Within the gastrointestinal tract, gene expression was detected in rumen, a ruminant-specific digestive organ, as well as stomach, duodenum and colon. Belongs to the endothelin/sarafotoxin family.