Effect of tamoxifen on TGF-β1 production in cultured fibroblasts. Concentration of TGF-β1 protein in the supernatant was measured after 48 hours of primary culture of renal fibroblasts (A) and culture of fibroblasts of the NRK-49F cell line (B), both stimulated with IL-1β and Ang-II. Medium, nonstimulated fibroblasts; TAM, fibroblasts incubated with tamoxifen; IL-1β, fibroblasts stimulated with IL-1β; Ang-II, fibroblasts stimulated with angiotensin-II; IL-1β+TAM, fibroblasts stimulated with IL-1β and treated with tamoxifen; Ang-II+TAM, fibroblasts stimulated with angiotensin-II and treated with tamoxifen.