Increased Plasma Endothelin-1 in Pulmonary Hypertension: Marker or Mediator of Disease?

Patient with pulmonary hypertension have substantial alterations in plasma immunoreactive endothelin-1, which may reflect changes in net release or clearance of endothelin-1 by the lung. In patients with primary pulmonary hypertension, the high levels in arterial compared with venous plasma suggest pulmonary production of endothelin-1, which may contribute to elevated pulmonary vascular resistance.