LEP and pulmonary arterial hypertension: We, therefore, sought (1) to determine if metformin alters leptin abundance in the plasma in our human metformin trial and rodent models of PAH, suggesting that it is modifiable; (2) to test the role of leptin in regulating metabolism in PAH in our two animal models of RV load stress; and (3) to test for synergism in cardiomyocyte lipid-stimulated metabolism with multiple metabolic interventions.