Accordingly, changes in MNA, Met2PY, Met4PY and 6-keto-PGF1α in the comparative stage of PAH development featured by approximately two folds elevation of plasma ET-1 concentration were quite similar, displaying increased plasma MNA concentration without changes in Met2PY, Met4PY and 6-keto-PGF1α plasma concentration. The gene discussed is EDN1; the disease is pulmonary arterial hypertension.