TGF-β1 decreased aromatase mRNA stability. Cells seated in 24-well plates were treated with 2 μg/ml actinomycin D alone or in combination with TGF-β1 (1 ng/ml). Cells were harvested at time 0 (pretreatment), 6, 12, 24, 36 and 48 h after treatment with TGF-β1. Aromatase mRNA levels were determined by semi-quantitative PCR. A) Representative results from one experiment. B) The half-life (T1/2) of aromatase transcript is defined as the time required for aromatse mRNA levels to drop to 50% of its starting values (0 time point). In this study, the T1/2 value of aromatse mRNA was reduced from 36 h in the control to 20 h in the treatment groups with TGF-β1. Data are mean ± SEM of three experiments. *, P < 0.05 verse the time matched control.