EDN1 and Increased circulating aldosterone concentration: Moreover, Park et al. demonstrated that aortic collagen and the media cross-sectional area were significantly increased in aldosterone-infused rats and that the administration of an endothelin-1 (ET-1) type A receptor antagonist prevented these effects, thereby suggesting a role for ET-1 in fibrosis of large vessels in conditions associated with mineralocorticoid excess [91].