FIG. 3.

The ER antagonist ICI 182780 specifically blocks the induction of luciferase activity by E2, PH, Cmpd 2 and 3 through ER in MCF-7 cells transiently transfected with a pERE-luciferase plasmid. Cells were treated with 1 nM E2, or 20 g/ml Ph-E or PhI; or 1 g/ml Cmpd 2 or 3 or 1 nM E2 + 1 M ICI 182780 or 20 g/ml PH or 1 g/ml Cmpd 2 or 3 + 1 M ICI 182780 to assess induction. Cells were treated for 16 h before they were lysed and reacted with substrate luciferin. Relative luciferase units were measured by luminometer. The PH extract, as well as Compounds 2 and 3 and E2 treatments significantly increased estrogen dependent activation of luciferase gene transcription in MCF-7 cells. ICI 182780 specifically blocked the actions of all in MCF-7 cells. Results are expressed as fold induction above control (DMSO vehicle solvent). Data represent the mean SD of three separate experiments performed in triplicate. * P < 0.01 versus control solvent (none) or **p < 0.05 versus E2. Abbreviation: Ph-E = Piper hispidum ethanol extract; Ph-I = Piper hispidum infusion.