Figure 4. The FSK induced GR resistance is specific for the CRH promoter. TAT3-luc (GRE-containing promoter) activity is expressed as percentage of maximal induction after 4 hours DEX treatment (filled bar; t = 0). All groups (hatched bars) were treated for 4 hours with DEX and only the time of onset of FSK treatment was different. Forskolin treatment strongly enhanced the transcriptional rate of GR at all time points (# indicates significantly different from DEX group with p,0.05). Pre-treatment with FSK resulted in the highest potentiation of the GR transcriptional rate. doi:10.1371/journal.pone.0004327.g004 References 1. Liu Y, Kamitakahara A, Kim AJ, Aguilera G (2008) Cyclic adenosine 39,59- monophosphate responsive element binding protein phosphorylation is required but not sufficient for activation of corticotropin-releasing hormone transcription. Endocrinology 149: 3512–3520. 2. 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