Figure 1.

 Effects of 17-β-oestradiol (E₂) on angiotensin II (Ang II) induced cell proliferation in cardiac fibroblasts. All experiments were performed by incorporation of [³H]thymidine into DNA. Increases in [³H]thymidine incorporation are each expressed relative to the [³H] content (100%) in their respective drug-free controls (C). All data are shown as the mean (SEM) for triplicate determinations for six cell preparations. *p < 0.05 v C; †p < 0.05 v Ang II alone. (A) E₂ inhibits Ang II induced DNA synthesis. Cells were preincubated with the indicated doses of E₂ and treated with Ang II (100 nmol/l) for 24 hours. [³H]thymidine incorporation was then assayed. (B) Effects of the oestrogen receptor antagonist ICI 182 780 (ICI) on E₂ mediated inhibition of Ang II induced DNA synthesis and lack of effect of 17-α-oestradiol (α-E) on Ang II induced DNA synthesis. Cells were preincubated with α-E (100 nmol/l), E₂ (100 nmol/l), or the combination of E₂ plus ICI (1 µmol/l) followed by either the application of Ang II (100 nmol/l) for 24 hours or its absence.