Luciferase Assay Stim. Concentration? - (Apr/26/2011 )

I am currently running a RapidReporter Gaussa Luciferase Assay and I have a question about the DAY:3 STimulation/Repression of Transcription step. The manual indicates that a 20x stock of transcriptional stim/inhibitor must be prepared and 10uL of that is added to the 96-well plate. My question is what the 1x concentration would be of that? I am looking to use Dexamethasone. Do any of you have any data indicating what are the commonly used concentrations of stims like DEXA or prednesalone, so I know how to make my 20x stock? I am currently on a time crunch so any help you can offer me as soon as you can is much appreciated. Thank you!

Here you can see a poster from promega in which they show dexamethasone having an EC50 at around 10-8 M in a reporter gene assay. For other news about reporter genes and nuclear receptor in general you can refer to my blog.

best wishes!