Detection of angiotensin converting enzyme mRNA in the rat heart by use of the polymerase chain reaction (PCR).

Abstract

Previous work has shown that angiotensin converting enzyme (ACE) activity and mRNA are present in cardiac tissue. Since ACE appears to be a key enzyme in the regulation of the activity of the cardiac renin angiotensin system, the aim of the present study was to examine the expression and regulation of ACE mRNA in the heart. ACE is a membrane bound enzyme with low synthetic turnover. We therefore investigated whether the highly sensitive polymerase chain reaction (PCR) can serve as a tool for detection and quantification of ACE mRNA in small tissue samples of the heart. Enzymatic reverse transcription was performed using 1 mg total RNA of atrial as well as of right and left ventricular origin. The resulting DNA was amplified in 25 cycles of PCR using Taq polymerase and specific primers. The amplification products were separated by agarose gel electrophoresis and detected by Southern blot analyses. Employing these methods, ACE mRNA was found in the atrium as well as right and left ventricles of rat hearts. Furthermore, PCR was useful to study the induction of ACE mRNA levels in left ventricles of hearts with experimental pressure overload hypertrophy as well right ventricles with compensatory hypertrophy after left ventricular infarction.