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. Author manuscript; available in PMC: 2010 Jan 27.
Published in final edited form as: Mol Cell Endocrinol. 2008 Oct 19;298(1-2):66–75. doi: 10.1016/j.mce.2008.10.011

Fig 2.

Fig 2

Refractory repression of the integrated MMTV after extended exposure (days) to dexamethasone. (A) Cells were exposed to a high (10−7M) or low (10−10M) dose of hormone for up to 48hrs. The integrated MMTV promoter was then tested for induction by treatment with an inducing dose of hormone (1 hr Dex 10−7M) and measured by luciferase expression. The mean of three trials and the standard error of the mean are shown normalized to the mean uninduced control. Exposure to either high or low concentration of hormone for 16 hrs or more attenuated induction (p<0.01). (B) The expression from the transient MMTV was measured by CAT expression in the same cells as in A. Exposure to either high or low concentration of hormone for 24 hrs or more enhanced induction (p<0.05). (C) Recovery of hormone induction. Cells were treated with dexamethasone for 72 hours. Hormone was then removed for 24 to 48 hours. The integrated MMTV was then induced with dexamethasone (10−7M) for 1 hour and expression was measured by luciferase activity. Recovery of induction correlates with time after exposure.