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Figure 2 Effect of angiotensin II (Ang II) on endothelin-1 (ET-1) gene expression in neonatal rat cardiac fibroblasts. (A) Time course of Ang II on ET-1 messenger RNA (mRNA) expression. Cells were incubated with Ang II (100 nM) for the indicated times. (B) Dose-dependent effect of Ang II on ET-1 mRNA expression. Cells were incubated with various doses of Ang II for 30 min. (C) Time course of Ang II-increased ET-1 promoter activity. Cardiac fibroblasts were transfected with chimeric ET-1 promoter-chloramphenicol acetyltransferase (CAT) fusion genes followed by treatment with Ang II (100 nM) for the time indicated or pretreated with losartan (Losa) (1 M) for 1 h followed by Ang II stimulation. (D) Induction of ET-1 promoter activity by different concentration of Ang II. Cells were harvested, and CAT activities were measured as described in the Experimental Procedures section. Control (C), no drugs; CAT2 and CAT3 are shown as positive and negative control; CAT activities are shown as the percentage of incorporation after normalizing to that of ß-galactosidase activities. Data are represented as difference relative to control groups. The results are shown as mean ± SEM (n = 3 per group). *p < 0.05 vs. control (Student t test); #p < 0.05 vs. Ang II alone (analysis of variance). The experiment was repeated three times with reproducible results.
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