Regression of chronic L-NAME-treatment-induced left ventricular hypertrophy: Effect of captopril

Long-term administration of N-G-nitro-L-arginine methyl ester (L-NAME) indu ces development of NO-deficient hypertension and left ventricular (LV) hype rtrophy. In this work, we examined the effect of spontaneous and captopril- induced recovery on LV hypertrophy and protein composition in rats with dev eloped L-NAME-induced hypertension. Four groups of rats were investigated: control; L-NAME 40 mg/kg/day for 4 weeks (L-NAME); L-NAME 40 mg/kg/day for 4 weeks followed by 3-week. spontaneous recovery (L-NAME+R); L-NAME 40 mg/k g/ day for 4 weeks followed by 3 weeks of captopril treatment at a dose of 100 mg/kg/day (L-NAME+C). LV hypertrophy in the L-NAME group was associated with an increase in content and concentration of left ventricular DNA and RNA, concentration of metabolic proteins (MP) and soluble collagenous prote ins (SCP). Spontaneous recovery period reduced the hypertension, without re gression of LV hypertrophy. Left ventricular DNA and RNA content were incre ased in the L-NAME+R group. In this group, concentrations of MP, contractil e proteins (CP), and collagenous proteins did not differ from those in the L-NAME group. Captopril treatment caused total regression of hypertension a nd LV hypertrophy and decreased both content and concentration of DNA and R NA, as well as the contests of MP, CP and SCP nu the L-NAME group. However, after captopril treatment, concentration of collagenous and non-collagenou s protein fractions remained increased nu control. We conclude that spontan eous regression of L-NAME-induced hypertension is not associated with regre ssion of LV hypertrophy, LV hypertrophy was regressed only in captopril-tre ated animals. (C) 2000 Academic Press