Coadministration of C-16, an angiotensin-converting enzyme 2 (ACE2) inhibitor, abolishes the protective effects of diminazene aceturate (DIZE). C-16 reversed the beneficial effects of DIZE on (A) right ventricular systolic pressure (RVSP), (B) right ventricular hypertrophy, (C) right ventricular end diastolic pressure (RVEDP), (D) +dP/dt, and (E) −dP/dt in the monocrotaline (MCT)-induced pulmonary hypertension model. Data represent mean ± SEM. ***P < 0.001 versus control subjects. #P < 0.05 compared with MCT and MDC groups (MDC represents the MCT+DIZE+C-16 group) (n = 6–8 per experimental group). +dP/dt and −dP/dt refer to rate of change in ventricular pressure with respect to time and characterize the systolic and diastolic function of the right ventricle, respectively.