ENDOTHELINS - MYOCARDIAL ACTIONS OF A NEW CLASS OF CYTOKINES

Endothelins are 21-amino acid peptides isolated originally from endothelial cells that are now known to be a nearly ubiquitous class of paracrine- and autocrine-acting peptide regulatory factors, or cytokines, with local activities in many tissues. Within the heart, endothelins have been shown to be among the most potent inotropic agents yet described, acting in part to sensitize the contractile elements to intracellular calcium. Endothelins have also been shown to increase the transcription of certain genes associated with myocardial growth and hypertrophy. Neither the principle cells of origin nor the factors that regulate endothelin's production and release within the heart are yet known but are the subjects of ongoing investigation.