However, whether or not hypoxia induced HIF-1α activation causes an analogous shift toward glycolytic metabolism in cells within the fetal lung remains unresolved; although chronic hypoxia induced HIF-1α activation is important to medial wall thickening associated with the development of pulmonary hypertension in various species (Yang et al., 2014), and delays surfactant protein production in the fetal sheep lung (Orgeig et al., 2015). Here, HIF1A is linked to pulmonary arterial hypertension.