Efficacy of monocrotaline pyrrole (MCTP) synthesis (A) and impact of MCTP and monocrotaline (MCT) on right heart hypertrophy (B) and pulmonary pressure (C) in Sprague Dawley rats. Quality and purity of the final product MCTP were assessed by thin layer chromatograms (A). Rats were either subcutaneously injected with monocrotaline (60 mg/kg body weight) or intravenously with monocrotaline pyrrole (5 mg/kg body weight) and its vehicle DMF. Right ventricle pressure was measured four weeks after MCT or MCTP by right heart catheterization in anaesthetized animals. Right heart hypertrophy was assessed by calculating right ventricle/left ventricle plus septum (RV/LV+S) weight ratio. *, p < 0.05 versus DMF group.