However, under chronic hypoxia (10% O2, 550 mbar), studies have shown some discrepancies with respect to the expression of Nox4 in the development of vasoconstriction of the pulmonary artery and subsequent pulmonary hypertension, indicating that this isoform can mediate different responses depending on the duration of hypoxia and the sex of the animals [76]. The gene discussed is NOX4; the disease is pulmonary arterial hypertension.