Effect of pentazocine (A) or cholesterol (B) on the inhibition of mitogenesis in different cell lines induced by SR31747A. (A) Two concentrations of (+) pentazocine were tested: control (○), 10−6 M (•) and 10−5 M (□). (B) Four cholesterol concentrations were tested: control (○), 1 μg ml−1 (•), 2 μg ml−1 (□), 10 μg ml−1 (▪) and 20 μg ml−1 (△). Treatments were performed in low lipid serum concentrations (0.1% FBS for breast cancer cell lines or 1% for prostate cell lines). Representative curves are shown: MCF7, MDA-MB-231 for breast cancer cell lines, and DU145 and PC3 for prostate cancer cell lines. The results are expressed as a percentage of MTT conversion measured in untreated cells.
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