The influence of nifedipine, verapamil, diltiazem, metoprolol, and enalapril on the basal and angiotensin II (Ang II)-induced elevation of [3H]thymidine incorporation into vascular smooth muscle cell (VSMC) DNA was examined. Our results from four independent experiments, each performed in triplicate, are summarized by calculating the half-maximal inhibitory concentration (IC50) of the drugs. Nifedipine, verapamil, and diltiazem had IC50 values of 2.3 +/- 0.7 x 10(-6), 3.5 +/- 0.3 x 10(-6), and 6.6 +/- 2.8 x 10(-6) M, respectively. Metoprolol had an IC50 value of 49 +/- 16 x 10(-6) M, whereas enalapril was completely ineffective. All drugs used had no influence on the basal cell [3H]thymidine incorporation. This in vitro study allows one to conclude that the calcium-entry blockers can inhibit the Ang II-induced cell growth and thus may have beneficial effects on the development and regression of vascular growth, which is associated with the pathogenesis of cardiovascular diseases.