REN and pulmonary arterial hypertension: Interestingly, chronic hypoxia induced activation of ACE2/Ang (1–7)/MasR axis and suppression of ACE/Ang II/AT1 receptor axis in lungs of pulmonary hypertensive Ren-2 transgenic rats (constructed by inserting the mouse Ren-2 renin gene) but not in normotensive transgene-negative control rats [60], suggesting that the baseline renin activity in hypertensive rats may be crucial to determine the differential response to hypoxia and that renin inhibition might be useful to inhibit the ACE to ACE2 pathway shift under hypoxic conditions.