HIF1A and pulmonary arterial hypertension: Pyruvate dehydrogenase kinase‐1 (PDK‐1), a key enzyme of the glycolytic pathway, is also a HIF1‐regulated protein and induces rapidly proliferation of cells by inhibiting their apoptosis.19 The fact that we also observe increased mRNA and protein expression of PDK‐1 in the lungs of MCT‐induced PAH rats, which strengthens our hypothesis of a metabolic basis of PAH development.