NPPA and pulmonary arterial hypertension: Thus, atrial natriuretic peptide expression, probably induced by stretch of the myocardium, was upregulated in the right ventricle from rats with pulmonary hypertension induced by either moncrotaline or hypoxia [8], [9], and in agreement with these findings, both natriuretic peptide precursor type A and B were markedly increased in the present study.