Inhibition of left ventricular hypertrophy and expression of proto-oncogenes c-myc other than c-fos in myocardium by early captopril treatment in SHR rats.

AIM

To explore the mechanisms by which angiotensin converting enzyme inhibitor (ACEI) prevents the development of left ventricular hypertrophy (LVH).

METHODS

Captopril (Cap 100 mg.kg(-1).d(-1)) was given orally to male spontaneously hypertensive rats from intrauterine period to 16 wk of age. Experiments were performed at 40 wk of age. SBP, left ventricular weight to body weight ratio (LVW/BW) were assessed. The levels of c-myc and c-fos mRNA in the left ventricle were measured by Northern blot.

RESULTS

Early-onset Cap therapy significantly decreased SBP. After discontinuance of treatment for 24 wk, SBP of SHRcap was still maintained at a lower level. LVW/BW in SHRcap was markedly reduced. The expression of myocardial c-myc mRNA was decreased by 72% in SHRcap compared with that in the untreated SHR, but the expression of myocardial c-fos mRNA was not different between the untreated SHR, SHRcap, and WKY rats.

CONCLUSION

Early Cap treatment may permanently prevent the development of hypertension, inhibit LVH. Furthermore, the prevention of LVH is associated with a decrease in c-myc mRNA levels, and the development and regression of left ventricular hypertrophy may be irrelevant to c-fos expression.