Aldosterone induces angiotensin-converting-enzyme gene expression in cultured neonatal rat cardiocytes

The cardiac renin-angiotensin-aldosterone system is activated in failing hearts in proportion to the severity of the disease. We hypothesized that a positive feedback mechanism might exist within this system and contribute to the progression of the heart failure. Methods and Results-- To test this hypothesis, we examined whether angiotensin II or aldosterone induces the expression of angiotensin-converting-enzyme (ACE) mRNA in cultured neonatal rat ventricular cardiocytes. Expression of ACE mRNA was detected and quantified using real-time reverse transcription-polymerase chain reaction. Exposure to angiotensin II (10(-5) mol/L) for 24 hours had no significant effect on the expression of ACE mRNA (0.7+/-0.5-fold versus control, P=NS), but similar treatment with aldosterone (10(-5) mol/L) induced a 23.3+/-7.9-fold increase (P